Grammar is divided into 2 types: Normative and Theoretical.
Normative (Practical) Grammar gives rules how to build correct forms of words and syntactical constructions. It teaches to write and speak correctly. Theoretical (Scientific) Grammar describes the language as a system, studies the components of that system and relations between them. Theoretical gr. explains and analyses the most difficult phenomena of a language. It gives different concepts of these phenomena and helps linguists to be guided in linguistic literature in order to form a certain opinion of this or that theoretical form. Grammar is divided also into 2 parts: Morphology and Syntax. Morphology is a part of Grammar which studies the most characteristic features of classes of words.
These classes are called parts of speech. Morphology studies not a single word, but the whole classes. Syntax is a part of Grammar which studies phrases and sentences, their structure, classification and combinations. Syntax is a system of 2 levels-that of phrases, that of sentences. It may be said that, in a way, morphology is more abstract than syntax, as it does not study connections between words actually used together in sentences, but connections between forms actually found in different sentences. In another way, however, morphology would appear to be less abstract than syntax, as it studies units of a smaller and more compact kind, whereas syntax deals with larger units, whose types and varieties are hard to number.