Morpheme is the immediate concern of a branch of linguistics called morphology, which studies the internal structure of words, and the rules by which words are formed. 对语素进行系统研究的语言学分支叫形态学，它研究词的内部结构和构造规则。
morpheme语素
it is the smallest unit of language in terms of relationship between expression and content. Morphemes themselves cannot be further analyzed. 语素是最小的语言单位，不能再进一步被划分为更小的单位。 Boxes 有两个语素：box, -es
lexeme词位
It can be understood as a family of word that differ only in their grammatical endings, for example the endings for number, case, tense, principle form, etc.
Lexeme: buy; Word forms: buy, bought, buying
word
stablity稳定性
The constituent构成的 parts of a complex word have little potent for rearrangement, compared with the relative positional mobility灵活性 of the constituents成分 of sentences in the hierarchy等级。
uninterruptibility相对的连续性
New elements are not to be inserted into a word.
dis-appoint-ment 三个不同的成分之间不可以再介入新的成分
the minimum free form最小的自由形式
Treating a sentence as the maximum free form and word as the minimum free form。 ————Bloomfield The word can be used freely. It can stand all by itself in a sentence in a language. Is Jane coming this evening？ ---Possibly.
