Abstract: Code- mixing in spontaneous speech has been widely
discussed, but not in virtual situations; especially in context of the
third language learning students. Thus, this study is an attempt to
explore the linguistic characteristics of the mixing of Japanese,
English and Thai in a mobile Line chat room by students with their
background of English as L2, Japanese as L3 and Thai as mother
tongue. The result found that insertion of Thai content words is a very
common linguistic phenomenon embedded with the other two
languages in the sentences. As chatting is to be ‘relational’ or
‘interactional’, it affected the style of lexical choices to be speech-like,
more personal and emotionally-related. A personal pronoun in
Japanese is often mixed into the sentences. The Japanese
sentence-final question particle か “ka” was added to the end of the
sentence based on Thai grammar rules. Some unique characteristics
were created while chatting.