Sound change based on Campbell (2004)
Introduction:
The sounds of languages tend to change overtime.
The question, then, is what kinds of sound change take place?
Kinds of sound change
1. Regular or sporadic
2. Conditioned or unconditioned
3. Phonemic or non-phonemic
1- Regular or sporadic
In general ‘sound laws admit of no exceptions’. That is, a change will take place wherever the sound which undergoes the change is found in the environment that conditions the change – e.g. in Spanish the sound change p>b/v_v took place wherever an original p appeared between vowels. Nonetheless, some changes are sporadic, affecting only one or a few words (e.g. OE spraec > ModE speech).
2- Conditioned or unconditioned
To say that a change is conditioned is to say that it only takes place under certain conditions (such as neighboring sounds, the position within a word, or a grammatical context). The Spanish change of p>b / v__v is an example of conditioned change.
Unconditioned change, on the other hand, takes place under all conditions. The Latin American Spanish change of lj>j (e.g. calle ‘street’ pronounced/kaje) is a good example of unconditioned change.
3- Phonemic or non-phonemic
Sound changes have different results. Some amount to little more than superficial reorganization of the surface sounds of speech (these are non-phonemic changes).
Others can cause deep structural alternations in the number of phonemic contrasts present in the language by adding or deleting phonemes (these are phonemic changes).
A phonemic change is defined as one which does affect the inventory of phonemes (distinctive sounds) by adding to or deleting from the number of phonemes.
An allophonic change is defined as one which does not affect the inventory of phonemes (distinctive sounds). In other words, the number of phonemes remains the same.