作者：Sun Fan
　　【Abstract】Synonymy has always been an emphasis and difficulty for linguists’ research. Taking the two synonyms “speak” and “talk” as an example， this paper tries to figure out the usage of the two words from the points of collocation and colligation based on COCA corpus. It finds that this two words have something in common， but still be different fundamentally.
　　【Key words】synonymy； collocation； colligation； semantic prosody； COCA
　　1. Introduction
　　Language is a system of arbitrary vocal symbols used for human communication. So， “say something” is really an important way to interchange information among human beings. In English， verb like “speak” or “talk” often plays a crucial role which acts as a core when people construct a whole sentence. Synonyms is a common relationship which means two lexical units sharing one meaning of different sense relations. But in daily use， we take it for grant that synonyms like “speak” and “talk” are totally the same， especially in some English-Chinese dictionaries， they are classified into the same type. Thus， Corpus’s data provides support for us to have further quantitative and qualitative analysis of synonyms.
　　We use The Corpus of Contemporary American English （COCA） for this research. The corpus contains more than 520 million words of text （20 million words each year from1990 to 2015）， and it is divided into spoken， fiction， popular magazines， newspapers， and academic texts. Corpus is a powerful tool for us to collect the index of “speak” and “talk”. Thus，， there is no doubt that we can choose it for our quantitative and qualitative analysis in authentic use.
　　2. Data distribution and analysis based on COCA
　　In language activities， synonyms are likely to show different distribution characteristics according to different registers. So， using COCA， we can know the frequency of “speak” and “talk” in authoritative texts explicitly.
　　2.1 Collocation
　　In linguistics， a collocation is a sequence of words or terms that co-occur more often than by chance. In phraseology， collocation is a sub-type of phraseme. An example of a phraseological collocation is the expression “dark ink”. While the same meaning could be conveyed by the roughly equivalent “heavy ink”， this expression is considered strange by native speakers.
　　There are about six main types of collocations：adjective+noun， noun+noun（such as collective noun）， verb+noun， adverb+adjective， verbs+prepositional phrase（phrase verb）， and verb+adverb.