Six phonemes with the R-colored vowel instead of the schwa ( cmudict-0.7b): It can be divided into seven phonemes and three syllables: There's a ~99% chance that the schwa does not represent an 'A' or 'I' in the first or middle part of syllables. However, the probability of the schwa being an 'A' in a middle part of a syllable is less than one percent (only 13 occurrences). When the schwa is in the final part of a syllable the most probable candidate for spelling is the letter 'A' (1419/3023 * 100 = 47.3%) followed by the letter 'I' (1332/3023 * 100 = 44.1%). The schwa sound is about twice as likely to correspond to the letter 'A' (23.9%) than to the letter 'E' (12.7%). 59):įrom this table we can calculate the schwa-letter correspondence: Based on phonological information alone about 49 percent of the 17,000 words in the corpus could be spelled correctly.īelow is a table with the 7 most popular graphemic options for the schwa sound in relation to the position within a syllable, adapted from Hanna et al.

The phonemes were matched to the graphemes of the words based on the Zipfian least effort principle. For instance the word 'string' would be separated into initial: S T R, medial: I, and final: NG. An algorithm scored whether a phoneme occurred in the first, the middle, or in the final part of a syllable. (1966) found that phoneme to grapheme correspondence is dependent upon the position of the phoneme within the syllable. The schwa predicts the spelling to some extent, although highly inconsistent in most cases.

What is a schwa