Linguistic evidence?

Question

How is linguistic evidence used to draw conclusions about the spread of peoples in China, Southeast Asia, the Pacific, and Africa?

Answer 1

languages are studied for similarities in word meanings and sounds.  If a word is the same across cultures it means that somehow or another that word was passed along from its point  of origin.  If words sound alike but have different meanings the word phoenically may have been transferred but the meaning misunderstood.  All languages are growing things that are influenced by peoples joining a culture.  They bring their words to the new place.

Answer 2

By studying the range of vocabulary of the lanuages used.

eg. the use of words relating to the tools, weather/climate, food, occupations, animals, religions etc.