white board with words for a language lessonThe most effective way to speak a new language quickly is to learn the 800 to 1,000 most common lemmas (word families). A lemma is a root word and all its variations, for example: do, does, did, doing; blue, bluer, bluest, blueish, etc. If you know the 800 most frequently-used lemmas in English, you'll understand 75% of everyday spoken English.      From How Many Words Do You Need to Speak a Language?