to reduce the different forms of a word to one single form, for example, reducing "builds", "building",or "built" to the lemma "build"

Compounds were lemmatized, that is, inflectional differences were disregarded. 把复合词按屈折变化形式归类，也就是忽略具体屈折变化而将之归为一组。

We used a lemmatised frequency list for the 8000 most frequent words in English. 我们把英文中8000个最常见词按屈折变化形式频率做了一个列表。