Assimilation is a process by which one sound takes on some or all the characteristics of a neighbouring sound. It is often used synonymously with coarticulation.Nasalization, dentalization and velarization are all instances of assimilation.

There are two possibilities of assimilation: if a following sound is influencing a preceding sound, it is regressive assimilation; the converse process, in which a preceding sound is influencing a following sound, is known as progressive assimilation.

For example, take “train” for illustration. When a sound “n” is added to it, thus resulting [trein], then the vowel [ei] will be nasalized. It is the regressive assimilation.Another example is if a nasal consonant [m] precedes an oral vowel [æ], some of the nasality will carry forward so that the vowel [æ] will begin with a somewhat nasal quality.It is the progressive assimilation.

本题考查音系学中的同化。 首先解释同化的含义及类型， 然后结合具体的同化例子进行分析。