Underlying the traditional linear syllabus is the notion that learning is a process of mastering each item perfectly, one at a time. In metaphorical terms, it was believed that a language develops in the same way as a building is constructed – one (linguistic) brick at a time.
However, the complexity of the acquisition process revealed by a growing body of second language acquisition research led some syllabus designers to argue that language development is basically an organic process. According to this metaphor, a new language develops in a way comparable to plants growing in a garden rather than a building being constructed. Learners do not acquire each item perfectly, one at a time, but numerous items imperfectly, all at once.
Needs analysis
With the advent of Communicative Language Teaching (CLT) in the 1970s, a very different syllabus approach was proposed by a number of linguists. This approach began, not with lists of grammatical, phonological and lexical features, but with an analysis of the communicative needs of the learner. Proponents of CLT argued that it was neither necessary nor possible to include every aspect of the target language in the syllabus. Rather, syllabus content should reflect the communicative purposes and needs of the learners.
Needs-based course design, particularly when it results in rigidly specified learning outcomes, has been heavily criticized. Widdowson (1983), for example, claims that such courses are exercises in training rather than in education because learners can only do those things for which they have been specifically prepared.
(David Nunan. Syllabus Design. In: M. Celce-Murcia (ed).
Teaching English as a second or foreign language. Boston, Massachusstes:
Heinle&Heinle. 3rd edition. 2001. Adaptado)