native language，official language，second language，foreign language的定义

Question

请问native language，official language，second language，foreign language的定义都是什么？在哪本书里能查到？
要英文正式的定义，我有胡壮麟和陈林华的语言学书，怎么都找不到定义呢

Answer 1

native language
本机语言, 机器各单元间编码语言 native language
词性及解释
【计】 本国语言

official language
官方语言

second language
n
a language other than the mother tongue that a person or community uses for public communication, esp in trade, higher education, and administration

a non-native language officially recognized and adopted in a multilingual country as a means of public communication
第二语言

foreign language
n.
外文,外语

好点的字典里应该都有涉及

Answer 2

本国语言，官方语言，第二语言，外国语
不知道在哪能找到

Answer 3

本国语言，官方语言，第二语言，外国语

Answer 4

语言学