Morphophonology

Morphophonology (or morphophonemics) looks at how morphology (the structure of words) interacts with phonology. In morphophonology one may talk about underlying or morpho-phonemic representations of words, which is a level of abstraction beneath the phonemic level. To see how this follows from the definition of morphophonology, it is necessary to look at an example. Compare the Biloxi words:

• de 'he goes' - da 'don't go'
• ande 'he is' - anda 'be!'
• ide 'it falls' - ide 'fall!'
• da 'he gathers' - da 'gather!'

Some also use this approach to deal with cases of neutralization and underspecification. Compare the Turkish words:

• et 'meat'
  • eti 'his meat'
• et 'to do'
  • edi 'he does'

Similar patterns in other words in Turkish show that while final stops are always devoiced, some will always voice when followed by a vowel added by suffixing, while the others always stay voiceless. Phonemically both ets must be represented as /et/, because phonemes are defined as the smallest units that may make words contrast (be distinguishable), so if we said the word for 'to do' was phonemically /ed/ then the two words would have to contrast! Still, we would like to say that on a more abstract level the word for 'to do' ends in a different segment, which doesn't surface (be realized) in some positions. The level of abstraction above the phoneme is known as an underlying or morpho-phonemic representation, and as is conventional we will indicate it here with pipes ||.^[1] Underlyingly, these Turkish words may be represented as |et|, |eti|, |ed|, and |edi|, and in the same way other Turkish words with this type of voicing alternation underlyingly end in a voiced stop, which surfaces as a voiceless phoneme when word-final.

The parallelism between the morpho-phonemic layer and the phonemic layer should be clear. Just like how phonemes surface as phones conditioned by their environment, underlying segments surface as phonemes. The important difference is that the surfacing of morpho-phonemic segments as phonemes occurs after morphological processes (e.g. adding endings on to words) take place. In a sense, morphophonology is morphologically informed, while plain phonology isn't.