INTRODUCTION:University students in the early twenty -first century use home computers and notebooks for communication at remarkable rates in ever -enlarging virtual communities (Tagliamonte, 2008).Taking into consideration, Facebook - the largest virtual community, has become one of the main communication media university students utilize to keep in contact with friends and acquaintances. Thus, this makes it an appealing medium of spoken -written language to identify trends of among university students in informal social domains.This paper aims to scrutinize a current language phenomenal trend in Malaysia by investigating Malay-English language alternation in the spoken -written language through the medium of Facebook. This is in contrast to previous research, has mostly studied language alternation in face -to-face informal conversations (Chan, 2004; Muysken, 2000; Myers -Scotten, 1992; Wei, 1998) with few studies in the context of Computer Mediated Communication i.e., CMC (Danet & Herring, 2003; Durham, 2003; Goldbarg, 2009; Ho, 2006; Huang, 2004).LANGUAGE ALTERNATION:The distinction between code-switching and is one of the most perplexing debates in the study of language alternation (Cardenas-Claros and Isharyanti, 2009; Myers -Scotton, 1993). Clyne (1991 as cited in Cardenas -Claros and Isharyanti, 2009) claimed that code -switching and refer to the same phenomena in which the speaker stops using language A' and employs language B' (p.161). Wei (1998) clarified that if language alternation occurs at or above clause level, it is considered as code-switching and if it occurs below clause level then it is considered as are the definitions adopted in this study.CODE-MIXING:Code-mixing is the change of one language to another within the same utterance or in the same oral/written text. Muysken (2000) defines as the lexical items and grammatical features of two languages that in the same sentence. According to Li (1998; 2000), code-mixing refers to any admixture of linguistic elements of two or more language systems in the same uttera nce at various levels: phonological, lexical, grammatical and orthographical.According to Muysken (2000), the term can be referred as when the features of grammar and lexical items of two or more languages are in the same sentence. In a multilingual society such as in Malaysia, is regarded as a common phenomenon generates mixed language or the localized term 'rojak' language. This phenomenon has given significant impact not only among language users in their daily normal day conversations, but have influenced sentence use in online social network such as Facebook. In this study, the narrow focus is on the language alternation of English morphemes into Malay lexical items where patterns of language choice are investigated. Language choice depends on the participants whether to choose Malay or English for their online postings, whilst morpheme insertion is in English language.Such communicative functions of code-switching can also be listed according to the functions that they try to accomplish. Among these, the following ten functions have been described in a study (Malik, 1994): Lack of Facility, Lack of Register, Mood of the Speaker, To emphasize a point, Habitual Experience, Semantic significance, To show identity with a group, To address a different audience, Pragmatic reasons and To attract attention.STATEMENT OF THE PROBLEM:In the past decade, people are communicating around the world without boundaries with the aid of technology. According to Crystal (2001), this type of communication has prompted new concepts of language contact. This has attracted many researchers to study on language contact via Computer-Mediated Communication (CMC) especially in bilingual communities (e.g., Paolillo, 2001;Su, 2003;Hinrichs, 2006 as cited in Huang, 2009). …