and /d/. By identifying the minimal pairs of a language, a phonologist can find out which sound substitutions cause differences of meaning.
2.8.2 The phoneme theory
2.8.3 Allophones
A phoneme is the smallest linguistic unit of sound that can signal a difference in meaning. Any of the different forms of a phoneme is called its allophones. E.g. in English, when the phoneme / / occurs at the beginning of the word like peak / /, it is said with a little puff of air, it is aspirated. But when / / occurs in the word like speak / /, it is said without the puff of the air, it is unaspirated. Both the aspirated [ ] in peak and the unaspirated [ =] in speak have the same phonemic function, i.e. they are both heard and identified as / / and not as / /; they are both allophones of the phoneme / /.
2.9 Phonological processes
2.9.1 Assimilation
Assimilation: A process by which one sound takes on some or all the characteristics of a neighboring sound.
Regressive assimilation: If a following sound is influencing a preceding sound, we call it regressive assimilation.