孤立语（Isolating language），是有低语素单词比（morpheme-per-word ratio）的语言。

依照语言学家的定义分类标准不同，孤立语与分析语之间的关系可能会产生三种情况：

相对于综合语（其中又分为黏着语、屈折语、多式综合语），孤立语/分析语在语素并不对语素进行变化，而是以语序表示文法关系。换言之，分析语无词形变化，即语素基本只有一种词形。

An isolating language is a type of language with a very low morpheme per word ratio. In the extreme case, each word contains a single morpheme.

A closely related concept is that of an analytic language, which uses little or no inflection to indicate grammatical relationships. Isolating and analytic languages tend to coincide and are often identified. However, an analytic language may still contain polymorphemic words due to the presence of derivational morphemes.