| Type: | Package |
| Title: | Phonetic Spelling Algorithms |
| Version: | 1.4.0 |
| Date: | 2026-08-09 |
| Encoding: | UTF-8 |
| URL: | https://phonics.jameshoward.us, https://github.com/k3jph/phonics-in-r |
| BugReports: | https://github.com/k3jph/phonics-in-r/issues |
| Description: | Provides a collection of phonetic algorithms including Soundex, Metaphone, NYSIIS, Caverphone, and others. The package is documented in <doi:10.18637/jss.v095.i08>. |
| License: | BSD_2_clause + file LICENSE |
| Imports: | Rcpp (≥ 0.12.1), data.table |
| Suggests: | testthat (≥ 3.0.0), knitr, rmarkdown, roxygen2 |
| LinkingTo: | Rcpp |
| VignetteBuilder: | knitr |
| Config/testthat/edition: | 3 |
| Config/roxygen2/version: | 8.1.0 |
| NeedsCompilation: | yes |
| Packaged: | 2026-08-10 01:02:15 UTC; runner |
| Author: | James Howard 
[aut, cre],
Kyle Haynes [ctb],
Amanda Hood [ctb],
Os Keyes [ctb] |
| Maintainer: | James Howard <jh@jameshoward.us> |
| Repository: | CRAN |
| Date/Publication: | 2026-08-23 11:20:08 UTC |
Phonetic spelling algorithms
Description
The phonics package provides phonetic encoders for English, German,
and French names, together with Match Rating Approach comparison and a
convenience dispatcher. See phonics for the complete method
list and vignette("phonics") for an overview.
Author(s)
Maintainer: James Howard jh@jameshoward.us (ORCID)
Authors:
James Howard jh@jameshoward.us (ORCID)
Other contributors:
Kyle Haynes [contributor]
Amanda Hood [contributor]
Os Keyes [contributor]
References
Howard, J. P., II (2020). "Phonetic Spelling Algorithm Implementations for R." Journal of Statistical Software, 95(8), 1–21. doi:10.18637/jss.v095.i08.
See Also
Useful links:
Report bugs at https://github.com/k3jph/phonics-in-r/issues
Caverphone
Description
The Caverphone family of phonetic algorithms
Usage
caverphone(word, maxCodeLen = NULL, modified = FALSE, clean = TRUE)
Arguments
word |
string or vector of strings to encode |
maxCodeLen |
maximum length of the resulting encodings, in characters |
modified |
if |
clean |
if |
Details
The variable maxCodeLen is the limit on how long the returned
Caverphone code should be. The default is 6, unless modified
is set to TRUE, then the default is 10.
The variable modified directs caverphone to use the
Caverphone2 method, instead of the original.
The caverphone algorithm is only defined for inputs over the
standard English alphabet, i.e., "A-Z.". Non-alphabetical
characters are removed from the string in a locale-dependent fashion.
This strips spaces, hyphens, and numbers. Other letters, such as
"Ü," may be permissible in the current locale but are unknown to
caverphone. For inputs outside of its known range, the output is
undefined and NA is returned and a warning is issued.
If clean is FALSE, caverphone attempts to process the
strings. The default is TRUE.
Value
the Caverphone encoded character vector
References
David Hood, "Caverphone: Phonetic matching algorithm," Technical Paper CTP060902, University of Otago, New Zealand, 2002.
David Hood, "Caverphone Revisited," Technical Paper CTP150804 University of Otago, New Zealand, 2004.
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
See Also
Other phonics:
cologne(),
lein(),
metaphone(),
mra_encode(),
nysiis(),
onca(),
phonex(),
phonics(),
rogerroot(),
soundex(),
statcan()
Examples
caverphone("William")
caverphone(c("Peter", "Peady"), modified = TRUE)
caverphone("Stevenson", maxCodeLen = 4)
Cologne Phonetic Name Coding
Description
The Cologne phonetic name coding procedure.
Usage
cologne(word, maxCodeLen = NULL, clean = TRUE)
Arguments
word |
string or vector of strings to encode |
maxCodeLen |
maximum length of the resulting encodings, in characters |
clean |
if |
Details
maxCodeLen = NULL preserves the algorithm's historical unbounded
output. An explicit nonnegative whole-number value truncates each code to
at most that many characters.
The cologne algorithm is only defined for inputs over the
standard English alphabet, i.e., "A-Z," "Ä," "Ö," "Ü," and
"ß." Non-alphabetical characters are removed from the string in a
locale-dependent fashion. This strips spaces, hyphens, and numbers.
Other letters, such as "ç," may be permissible in the current locale
but are unknown to cologne. For inputs outside of its known
range, the output is undefined and NA is returned and a
warning is issued. If clean is FALSE,
cologne attempts to process the strings. The default is
TRUE.
Value
the Cologne encoded character vector
References
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
Hans Joachim Postel. "Die Koelner Phonetik. Ein Verfahren zur Identifizierung von Personennamen auf der Grundlage der Gestaltanalyse." IBM-Nachrichten 19. Jahrgang, 1969, p. 925-931.
See Also
Other phonics:
caverphone(),
lein(),
metaphone(),
mra_encode(),
nysiis(),
onca(),
phonex(),
phonics(),
rogerroot(),
soundex(),
statcan()
Examples
cologne("William")
cologne(c("Peter", "Peady"))
cologne("Stevenson", maxCodeLen = 8)
Lein Name Coding
Description
The Lein name coding procedure.
Usage
lein(word, maxCodeLen = 4, clean = TRUE)
Arguments
word |
string or vector of strings to encode |
maxCodeLen |
maximum length of the resulting encodings, in characters |
clean |
if |
Details
The variable word is the name to be encoded. The variable
maxCodeLen is the limit on how long the returned name code
should be. The default is 4.
The lein algorithm is only defined for inputs over the
standard English alphabet, i.e., "A-Z.". Non-alphabetical
characters are removed from the string in a locale-dependent fashion.
This strips spaces, hyphens, and numbers. Other letters, such as
"Ü," may be permissible in the current locale but are unknown to
lein. For inputs outside of its known range, the output is
undefined and NA is returned and a warning is issued.
If clean is FALSE, lein attempts to process the
strings. The default is TRUE.
Value
the Lein encoded character vector
References
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
Billy T. Lynch and William L. Arends. "Selection of surname coding procedure for the SRS record linkage system." United States Department of Agriculture, Sample Survey Research Branch, Research Division, Washington, 1977.
See Also
Other phonics:
caverphone(),
cologne(),
metaphone(),
mra_encode(),
nysiis(),
onca(),
phonex(),
phonics(),
rogerroot(),
soundex(),
statcan()
Examples
lein("William")
lein(c("Peter", "Peady"))
lein("Stevenson", maxCodeLen = 8)
Generate phonetic versions of strings with Metaphone
Description
The function metaphone phonetically encodes the
given string using the metaphone algorithm.
Usage
metaphone(word, maxCodeLen = 10L, clean = TRUE)
Arguments
word |
string or vector of strings to encode |
maxCodeLen |
maximum length of the resulting encodings, in characters |
clean |
if |
Details
Metaphone has accumulated incompatible implementation variants. This function follows the traditional rules from Philips' 1990 algorithm; it is therefore not expected to reproduce PHP or Apache Commons Codec for every input.
The variable maxCodeLen is the limit on how long the returned
metaphone should be.
The metaphone algorithm is only defined for inputs over the
standard English alphabet, i.e., "A-Z.". Non-alphabetical
characters are removed from the string in a locale-dependent fashion.
This strips spaces, hyphens, and numbers. Other letters, such as
"Ü," may be permissible in the current locale but are unknown to
metaphone. For inputs outside of its known range, the output
is undefined and NA is returned and a warning this
thrown. If clean is FALSE, metaphone attempts
to process the strings. The default is TRUE.
Value
a character vector containing the metaphones of word,
or an NA if the word value is NA
References
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
Lawrence Philips, "Hanging on the Metaphone," Computer Language, vol. 7, no. 12 (1990), p. 38–44.
See Also
Other phonics:
caverphone(),
cologne(),
lein(),
mra_encode(),
nysiis(),
onca(),
phonex(),
phonics(),
rogerroot(),
soundex(),
statcan()
Examples
metaphone("wheel")
metaphone(c("school", "benji"))
Match Rating Approach Encoder
Description
The Western Airlines matching rating approach name encoder
Usage
mra_encode(word, clean = TRUE)
mra_compare(x, y)
Arguments
word |
string or vector of strings to encode |
clean |
if |
x |
MRA-encoded character vector |
y |
MRA-encoded character vector |
Details
The variable word is the name to be encoded. The variable
maxCodeLen is not supported in this algorithm encoder
because the algorithm itself is dependent upon its six-character
length. The variables x and y are MRA-encoded and are
compared to each other using the MRA comparison specification.
The mra_encode algorithm is only defined for inputs over the
standard English alphabet, i.e., "A-Z.". Non-alphabetical
characters are removed from the string in a locale-dependent fashion.
This strips spaces, hyphens, and numbers. Other letters, such as
"Ü," may be permissible in the current locale but are unknown to
mra_encode. For inputs outside of its known range, the output is
undefined and NA is returned and a warning is issued.
If clean is FALSE, mra_encode attempts to process the
strings. The default is TRUE.
Value
The mra_encode function returns match rating approach
encoded character vector. The mra_compare returns a boolean
vector which is TRUE if x and y pass the MRA
comparison test.
References
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
G.B. Moore, J.L. Kuhns, J.L. Treffzs, and C.A. Montgomery, Accessing Individual Records from Personal Data Files Using Nonunique Identifiers, US National Institute of Standards and Technology, SP-500-2 (1977), p. 17.
See Also
Other phonics:
caverphone(),
cologne(),
lein(),
metaphone(),
nysiis(),
onca(),
phonex(),
phonics(),
rogerroot(),
soundex(),
statcan()
Examples
mra_encode("William")
mra_encode(c("Peter", "Peady"))
mra_encode("Stevenson")
New York State Identification and Intelligence System
Description
The NYSIIS phonetic algorithm
Usage
nysiis(word, maxCodeLen = 6, modified = FALSE, clean = TRUE)
Arguments
word |
string or vector of strings to encode |
maxCodeLen |
maximum length of the resulting encodings, in characters |
modified |
if |
clean |
if |
Details
The nysiis function implements the original NYSIIS
character scan described by Taft and the USDA modified scan documented by
Lynch and Arends.
The variable maxCodeLen is the limit on how long the returned
NYSIIS code should be. The default is 6.
Set modified = TRUE for the USDA variant. That publication classifies
names ending in JR or SR as errors; this function warns and
returns NA for those inputs.
The nysiis algorithm is only defined for inputs over the
standard English alphabet, i.e., "A-Z.". Non-alphabetical
characters are removed from the string in a locale-dependent fashion.
This strips spaces, hyphens, and numbers. Other letters, such as
"Ü," may be permissible in the current locale but are unknown to
nysiis. For inputs outside of its known range, the output is
undefined and NA is returned and a warning is issued.
If clean is FALSE, nysiis attempts to process the
strings. The default is TRUE.
Value
the NYSIIS encoded character vector
References
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
Robert L. Taft, Name search techniques, Bureau of Systems Development, Albany, New York, 1970.
Billy T. Lynch and William L. Arends, Selection of a Surname Coding Procedure for the SRS Record Linkage System, United States Department of Agriculture, 1977, Appendix B.
See Also
Other phonics:
caverphone(),
cologne(),
lein(),
metaphone(),
mra_encode(),
onca(),
phonex(),
phonics(),
rogerroot(),
soundex(),
statcan()
Examples
nysiis("Robert")
nysiis("rupert")
nysiis(c("Alabama", "Alaska"), modified = TRUE)
nysiis("mississippi", 4)
Oxford Name Compression Algorithm
Description
The Oxford Name Compression Algorithm name coding procedure
Usage
onca(word, maxCodeLen = 4, clean = TRUE, modified = FALSE, refined = FALSE)
Arguments
word |
string or vector of strings to encode |
maxCodeLen |
maximum length of the resulting encodings, in characters |
clean |
if |
modified |
if |
refined |
if |
Details
ONCA applies NYSIIS and then Soundex. Gill describes the first stage as an
"anglicised" NYSIIS but does not publish its complete rule set; this
implementation uses the documented standard NYSIIS scan. The
modified and refined combinations are package extensions.
maxCodeLen bounds the final code and defaults to 4.
The onca algorithm is only defined for inputs over the
standard English alphabet, i.e., "A-Z.". Non-alphabetical
characters are removed from the string in a locale-dependent fashion.
This strips spaces, hyphens, and numbers. Other letters, such as
"Ü," may be permissible in the current locale but are unknown to
onca. For inputs outside of its known range, the output is
undefined and NA is returned and a warning is issued.
If clean is FALSE, onca attempts to process the
strings. The default is TRUE.
Value
the ONCA encoded character vector
References
Gill, L. E. (1997). "OX-LINK: The Oxford Medical Record Linkage System." In Record Linkage Techniques—1997, p. 15–33.
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
See Also
Other phonics:
caverphone(),
cologne(),
lein(),
metaphone(),
mra_encode(),
nysiis(),
phonex(),
phonics(),
rogerroot(),
soundex(),
statcan()
Examples
onca("William")
onca(c("Peter", "Peady"))
onca("Stevenson", maxCodeLen = 8)
Phonex Name Coding
Description
The Phonex name coding procedure.
Usage
phonex(word, maxCodeLen = 4, clean = TRUE)
Arguments
word |
string or vector of strings to encode |
maxCodeLen |
maximum length of the resulting encodings, in characters |
clean |
if |
Details
The variable word is the name to be encoded. The variable
maxCodeLen is the limit on how long the returned name code
should be. The default is 4.
The phonex algorithm is only defined for inputs over the
standard English alphabet, i.e., "A-Z," "Ä," "Ö," "Ü," and
"ß." Non-alphabetical characters are removed from the string in a
locale-dependent fashion. This strips spaces, hyphens, and numbers.
Other letters, such as "ç," may be permissible in the current locale
but are unknown to phonex. For inputs outside of its known
range, the output is undefined and NA is returned and a
warning is issued. If clean is FALSE,
phonex attempts to process the strings. The default is
TRUE.
Value
the Phonex encoded character vector
References
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
A.J. Lait and Brian Randell. "An assessment of name matching algorithms." Technical Report Series-University of Newcastle Upon Tyne Computing Science (1996).
See Also
Other phonics:
caverphone(),
cologne(),
lein(),
metaphone(),
mra_encode(),
nysiis(),
onca(),
phonics(),
rogerroot(),
soundex(),
statcan()
Examples
phonex("William")
phonex(c("Peter", "Peady"))
phonex("Stevenson", maxCodeLen = 8)
Phonetic Spelling Algorithms
Description
Apply one or more phonetic encoders to a character vector and return their codes together in a data frame.
Usage
phonics(word, method, clean = TRUE)
Arguments
word |
A character vector to encode. |
method |
A character vector naming the methods to apply. |
clean |
If |
Details
Available methods are "caverphone",
"caverphone.modified", "cologne", "lein",
"metaphone", "nysiis", "nysiis.modified",
"onca", "onca.modified", "onca.refined",
"onca.modified.refined", "phonex",
"rogerroot", "soundex", "soundex.refined", and
"statcan". Unknown method names produce a warning and no result
column.
Value
A data frame whose first column is word, followed by one character
column for each recognized method.
References
Howard, J. P., II (2020). "Phonetic Spelling Algorithm Implementations for R." Journal of Statistical Software, 95(8), 1–21. doi:10.18637/jss.v095.i08.
See Also
Other phonics:
caverphone(),
cologne(),
lein(),
metaphone(),
mra_encode(),
nysiis(),
onca(),
phonex(),
rogerroot(),
soundex(),
statcan()
Examples
phonics(c("Peter", "Peady"), c("soundex", "soundex.refined"))
Roger Root Name Coding Procedure
Description
Provides the Roger Root name coding system
Usage
rogerroot(word, maxCodeLen = 5, clean = TRUE)
Arguments
word |
string or vector of strings to encode |
maxCodeLen |
maximum length of the resulting encodings, in characters |
clean |
if |
Details
The rogerroot function phonetically encodes the given string
using the Roger Root algorithm. The variable word is a string
or vector of strings to encode.
The variable maxCodeLen is the limit on how long the returned
code should be. The default is 5.
The rogerroot algorithm is only defined for inputs over the
standard English alphabet, i.e., "A-Z.". Non-alphabetical
characters are removed from the string in a locale-dependent fashion.
This strips spaces, hyphens, and numbers. Other letters, such as
"Ü," may be permissible in the current locale but are unknown to
rogerroot. For inputs outside of its known range, the output
is undefined and NA is returned and a warning this
thrown. If clean is FALSE, rogerroot attempts
to process the strings. The default is TRUE.
Value
the Roger Root encoded character vector
References
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
Billy T. Lynch and William L. Arends, Selection of a Surname Coding Procedure for the SRS Record Linkage System, United States Department of Agriculture, 1977, Appendix B.
See Also
Other phonics:
caverphone(),
cologne(),
lein(),
metaphone(),
mra_encode(),
nysiis(),
onca(),
phonex(),
phonics(),
soundex(),
statcan()
Examples
rogerroot("William")
rogerroot(c("Peter", "Peady"))
rogerroot("Stevenson")
Soundex
Description
The Soundex phonetic algorithms
Usage
soundex(word, maxCodeLen = 4L, clean = TRUE)
refinedSoundex(word, maxCodeLen = 10L, clean = TRUE)
Arguments
word |
string or vector of strings to encode |
maxCodeLen |
maximum length of the resulting encodings, in characters |
clean |
if |
Details
The function soundex phonetically encodes the given
string using the U.S. census Soundex rules. The function
refinedSoundex implements the U.S.-English mapping and duplicate
handling from Apache Commons Codec's Refined Soundex.
The variable maxCodeLen is the limit on how long the returned
soundex should be.
The soundex and refinedSoundex algorithms are only
defined for inputs over the standard English alphabet, i.e.,
"A-Z." Non-alphabetical characters are removed from the string in a
locale-dependent fashion. This strips spaces, hyphens, and numbers.
Other letters, such as "Ü," may be permissible in the current locale
but are unknown to soundex and refinedSoundex. For
inputs outside of its known range, the output is undefined and
NA is returned and a warning is issued. If
clean is FALSE, soundex and
refinedSoundex attempts to process the strings. The default
is TRUE.
Value
soundex encoded character vector
Caveats
The soundex and refinedSoundex algorithms are only
defined for inputs over the standard English alphabet, i.e.,
"A-Z." For inputs outside this range, the output is undefined.
References
Charles P. Bourne and Donald F. Ford, "A study of methods for systematically abbreviating English words and names," Journal of the ACM, vol. 8, no. 4 (1961), p. 538-552.
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
Howard B. Newcombe, James M. Kennedy, "Record linkage: making maximum use of the discriminating power of identifying information," Communications of the ACM, vol. 5, no. 11 (1962), p. 563-566.
United States National Archives and Records Administration, "The Soundex Indexing System."
Apache Software Foundation, Apache Commons Codec: RefinedSoundex.
See Also
Other phonics:
caverphone(),
cologne(),
lein(),
metaphone(),
mra_encode(),
nysiis(),
onca(),
phonex(),
phonics(),
rogerroot(),
statcan()
Examples
soundex("wheel")
soundex(c("school", "benji"))
Statistics Canada Name Coding
Description
The modified Statistics Canada name coding procedure
Usage
statcan(word, maxCodeLen = 4, clean = TRUE)
Arguments
word |
string or vector of strings to encode |
maxCodeLen |
maximum length of the resulting encodings, in characters |
clean |
if |
Details
The variable word is the name to be encoded. The variable
maxCodeLen is the limit on how long the returned name code
should be. The default is 4.
The statcan algorithm is only defined for inputs over the
standard French alphabet. Non-alphabetical characters are removed
from the string in a locale-dependent fashion. This strips spaces,
hyphens, and numbers. Other letters, such as "Ü," may be permissible
in the current locale but are unknown to statcan. For inputs
outside of its known range, the output is undefined and NA is
returned and a warning is issued. If clean is
FALSE, statcan attempts to process the strings. The
default is TRUE.
Value
the Statistics Canada encoded character vector
References
James P. Howard, II, "Phonetic Spelling Algorithm Implementations for R," Journal of Statistical Software, vol. 95, no. 8, (2020), p. 1–21, <10.18637/jss.v095.i08>.
Billy T. Lynch and William L. Arends. "Selection of surname coding procedure for the SRS record linkage system." United States Department of Agriculture, Sample Survey Research Branch, Research Division, Washington, 1977.
See Also
Other phonics:
caverphone(),
cologne(),
lein(),
metaphone(),
mra_encode(),
nysiis(),
onca(),
phonex(),
phonics(),
rogerroot(),
soundex()
Examples
statcan("William")
statcan(c("Peter", "Peady"))
statcan("Stevenson", maxCodeLen = 8)