This thesis defines "initial consonant error" as the regular and systematical initial sounds, which are general in the speech of early children with a common physiological mechanism basis and different from those of adults.

The author of this article ana- lyzes different stages of children s mother tongue acquisition,sums up the differences and similarities between mother tongue acquisition and foreign language acquisition,points out some common errors made by children and proposes some constructive ideas.

Therefore,it is suggested to learn from mother tongue acquisition the successive factors with a purpose to better our foreign language learning and teaching.

UG which was originated from L1 acquisition study aims to set up a language acquisition model adopted by young learners in different language environment.

Under the Framework of Universal Grammar this article discusses the difference between L1 acquisition of children and foreign language learning of adults in terms of L1 and L2, the learners, the initial state, process and the final state of acquisition; It is hoped that this will bring inspiration for foreign language teaching and learning.

It is very helpful in first language acquisition(FLA) and explains reasonably many practical problems.

This paper discusses the positive relevance between Grammaticalization and First Language Acquisition in two factors: 1)children s acquisition of function words in their first language;2)the grammaticalization features in the process of children s first language acquisition with regard to their linguistic structures.

Based on the assumption that learners internal mental development is the determinant factor in the course of learning,to put foreign language teaching in a solid theory framework,a clear understanding of the differences between child first language acquisition and adult foreign language learning is a must.