Rakesh Patel (2009) says that the Traditional Grammar term is applied to summarize the range of methods found in the pre-linguistic era of grammatical study. The whole approach of this method emphasizes on correctness, linguistic purism, literary excellence, the priority of the written mode of language and the use of Latin models.
The very beginning of the twentieth century was typically marked by a new approach to grammar as suggested by linguists such as Ferdinand de Saussure and American linguist like Frantz Boas, Bloomfield and Edward Sapir. Their approach is called structuralism whose aim was to arouse a reaction against the approach of the traditional grammarians.
Traditional grammarians considered Latin as their model because English is a part of the Indo-European family of languages, and to which Latin and Greek also belong. It did have similar grammatical elements.
If you study the form of traditional grammar, the rules of classical languages were followed considering that English did not have grammar of its own. And English followed Latin grammar. Besides the parts of speech, traditional grammatical analysis also makes use of numerous other categories, just like 'number', 'gender', 'person', 'tense' and 'voice'.
For example, gender was not natural. It was grammatical in traditional grammar. As you see here "The man loves his bike". Gender, in this example, is used for describing the agreement between 'man' and 'his'. In English, you need to describe this relationship in terms of natural gender based upon a biological distinction between male and female. Such biological distinction is different compared to the common distinction found in languages which employ grammatical gender.
Traditional grammar has some limitations as it occurs with some static verbs that do not occur in a progressive form, for instance "I am knowing" or in the imperative mood like "Know!" Traditional grammar sometimes fails to account for certain things like ambiguous sentences just like "While thinking about the queen the Honda hit the fence".
http://ezinearticles.com/?Traditional-Grammar---Studying-the-Approach-of-Traditional-Grammarians&id=1765312
So, in conclusion, we can define traditional grammar as The collection of prescriptive rules and concepts about the structure of language that is commonly taught in schools; and we say that traditional grammar is prescriptive because it focuses on the distinction between what some people do with language and what they ought to do with it, according to a pre-established standard.
The chief goal of traditional grammar, therefore, is perpetuating a historical model of what supposedly constitutes proper language."
(James D. Williams, The Teacher's Grammar Book. Routledge, 2005)
