This study focuses on computer mediated communication (CMC) in instant messaging using the Basque language in a context where exposure to English is very limited outside the classroom. This context provides an opportunity to analyze the universality of linguistic features identified in CMC in English. The corpus consists of 54 naturalistic dyadic conversations between Basque secondary school students, using the medium of instant messaging. Thirty-four of those students then took part in six focus group discussions so as to obtain information about their perception of the linguistic features used in instant messaging. The results indicate that the linguistic features used in CMC are in general terms similar in English and Basque with some exceptions which are related to the specific linguistic features of the Basque language.