A national language is the language of a political, cultural and social unit. It is general developed and used as a symbol of national unity. Its functions are to identity the nation and unite its people. The national language in Singapore is Malay. It reflects both the historical and geographical position of the country.

An official language is a language which may be used for government business. Its function is primary utilitarian rather than symbolic. Singapore has four official languages – Malay, Mandarin, English and Tamil.

Mother tongue is the superordinate language of one’s official ethnic group. So, the mother tongue of a ‘Chinese’ is deemed to be Mandarin, that a ‘Malay’ Malay and that a ‘Tamil’ or ‘Malayalee’ Tamil.

The first language is the main medium of education studied, which is now always English.

The second language is the other language studied, which is usually the official mother tongue.

The term bilingual is often used in Singapore to refer to a person who has succeeded in both the language learnt at school.

A major language is defined as (a) a language which is spoken as a native language by more than 25% of the population or more than one million people in the society, (b) an official language of the nation and (c) is the language of education of over 50% of the secondary school graduates of the nation. There are five major languages in Singapore – English, Mandarin, Malay, Tamil and Hokkien.

A lingua franca is a language used for communication between people whose first language differs. Both Malay and English could be qualified as the lingua franca in Singapore for inter-group communication. Mandarin has also gained ground to become the lingua franca among the Chinese in Singapore.

Source : “English in New Cultural Contexts”. Published by The Singapore Institute of Management. “An Introduction to Sociolinguistics” by Janet Holmes. Published by Pearson Education Limited, UK.