In linguistics, traditional grammar is the collection of prescriptive rules and concepts about the structure of language that is commonly taught in schools. It is prescriptive because it focuses on the distinction between what some people do with language and what they ought to do with it and the concepts treated in traditional grammars include, subject, predicate, object, complement, noun, adjective, determiner, verb, adverb, preposition, conjunction, pronoun, etc.
The functional grammar is concerned with the way that the different kinds of meaning that contribute to grammatical structure are comprehensively addressed. It is concerned with resources for:
- analysing experience - what is going on
- analysing interaction - who is communicating with whom
- analysing the ways in which messages are constructed
In addition it is concerned with recourses for combining clauses into clause complexes (sentences)
Talking about the differences between traditional grammar and functional grammar, the traditional grammar is correct "textbook" grammar but functional grammar is colloquial grammar, grammar that people use in regular conversation. For instance, people tend to say "Who are you going with?" even though that is incorrect and the correct form would be "With whom are you going?" (Prepositions should always precede their objects, and "who" should be in the objective case "whom").
Traditional grammar mainly focuses on the role and meaning of individual words and functional grammar is more concerned with units of meaning and typically groups words into units of contextual meaning. The functional grammar is particularly useful for teaching language and literacy skills due to the focus on meaning.From those information’s above, we can conclude that traditional grammar is particularly useful for explaining layers of language at the sentence level and below, e.g. sentences, clauses, phrases, words, prefixes, suffixes and word-formation. Traditional grammar is not a unified theory or model of language - its terms and categories can be used in all kinds of ways, including descriptively (describing what people say), analytically (assigning categories and functions to language elements) or prescriptively (telling people what is correct, sometimes arbitrarily). Whereas, functional grammar is particularly helpful for explaining how language is selected and organised in particular ways for particular socio-cultural purposes. Important variables for describing such different usages are field (information), tenor (formality) and mode (spoken/written). In classroom contexts, functional grammar has been associated with genres, which are predictable, identifiable ways of using language. Other systemic functional grammar terms which people might have heard include circumstance, participant and process.