Given both a word and the corresponding IPA, how to match/map the letters together?

Question

Given both the word and the corresponding IPA equivalent, is there any stable algorithm for mapping the letter of each word to the IPA letter?

For example, given close-quote and IPA kloʊzkwoʊt -- I'd want to create a mapping along the lines of:

c -> k

l -> l

o -> oʊ

s -> z

e ->

q -> kw

uo -> oʊ

t -> t

e ->

I'm very much open to different representations of the mapping, but this is at least the gist of the question. Ad-hoc matching of vowels etc. haven't given me a lot of luck in the general case... Any tips for doing this, or pointers on how to do it?

Answer 1

Yes, there is an algorithm and even a readily available tool for this task. The tool is the Helsinki Finite State Transducer. I have seen an application of it to historical linguistics and determining proto-languages and sound changes from cognate lists (for uralic languages), but in principle it should also do alignment of spelling and IPA representation.

Answer 2

You might get somewhere with some languages, but I doubt you'll have great success with this in English, for example.

One reason is that English has many words for which there is no single pronunciation, but a variety of different pronunciations depending on the enviroment of the word. So, for example, in British English, the word are could be any of these:

• /ə/
• /ər/
• /ɑ:/
• /ɑ:r/

Which one you get depends on whether the word is stressed or not, or stranded or not, plus whether it is followed by a vowel or not.

Secondly, there is the problem of silent letters. How could we meaningfully map the E at the end of are? How about CH in yacht or T in listen?

Another complication you have is discontinuous spelling rules. So, for example take the word:

• tome /toʊm/ (American English)

Here you cannot really just map the O onto the /oʊ/. It is represented in the orthography by the O and the E occurring on either side of a consonant.

However, you might be able to get quite a long way. It also depends what exactly the mapping is for, and what you mean by mapping phonemes onto letters. For example suppose you have the noun minute, in what sense does the U map onto /ɪ/? (And again what are you doing with the E there?) In some sense maybe, but it's not clear - or maybe it's just not clear to me.

Answer 3

Phonetisaurus can do that:

https://github.com/AdolfVonKleist/Phonetisaurus

There is a strict 1-1 correspondence between the 2 rows:

c  l  o  s  e  <eps>  
K L OW1 Z _ <eps> 

q  u  o  t  e  <eps>  
K W OW1 T _ <eps> 

Python code:

import phonetisaurus
model = phonetisaurus.Phonetisaurus ("../../train/model.fst")

results = model.Phoneticize ("close",
    1, # n best
    500, # beam size
    10.0, # n best threshold
    False, # write_fsts
    False, # accumulate
    0.0 # target probability mass
    )

for result in results :
    for ilab in result.ILabels:
        print (model.FindIsym(ilab), end="  ")
    print()

    for olab in result.OLabels:
        print (model.FindOsym(olab), end=" ")
    print()

but you need to follow the GitHub instructions to install Phonetisaurus, install Python bindings, and train the model.

In the end I don't find it very useful for my purpose, but others may :)