make it understandable 和 by which it is understood在意义上市不一样的。 过程可以使language更好理解,而不是通过这个过程(我觉得这个地方by 可以认为指“通过……”),语言就被理解了,逻辑不通,因为可以理解并不等于被理解了,至少没有make it understandable 好。
The psychology of language, including production and understanding in utterances; from speech sounds to speaker’s meaning; children’s acquisition of the first language; and the psychological basis for language systems. Language functions in natural contexts and their relation to the processes by which language is produced, understood, and acquired.