A diversity of dynamics can influence the child’s dual language development, which do not seem to cause delays in early language development milestones. Also, beyond the early months, language development generally occurs in bilinguals within the normal range, as determined by monolingual children, for some language aspects, whilst it could lag behind monolinguals’ development in some other aspects. Nevertheless, these differences do not lead to any difficulties in the child’s development and can be explained by examining, in most instances, the relationship between the child’s dominant and non-dominant language. In fact, it is unlikely for pre-school bilingual children to achieve a balanced proficiency in both languages, whilst most probably they will be dominant in one language. Also school age bilingual children could maintain a dominant language depending on the amount of language input they receive. Empirical research demonstrates that bilingual children could lag behind monolingual children in their non-dominant language in the vocabulary acquisition as bilingual children tend to have smaller vocabulary compared to their monolingual peers. This appears to be logical considering that bilingual children possess identical cognitive abilities and limitations related to memory capacity as monolingual children. Recent research confirms that language exposure influences bilingual children’s performance with regards to the acquisition of vocabulary. In fact, Thordadottir (2011) studied the performance of receptive and expressive vocabulary in 5 year old children of Montreal who were learning English and French simultaneously and compared their performance to monolingual children. The children had the same age, socio-economic status and non-verbal cognition. Also, the bilingual children spoke languages with equal status. The only variable was the amount of exposure to each language the children received across the bilingual process. Children exposed to both languages equally, achieved the same results as their monolingual peers in receptive vocabulary, whilst a greater exposure was required to attain the same monolingual’s outcomes in expressive vocabulary. In contrast to several previous studies, the bilingual children examined did not show a significant gap correlated to monolingual children in receptive vocabulary. This optimistic result could be attributed to the positive language-learning conditions for English and French in Montreal, but it could be also related to the fact that there is not a great typological distance between the two languages. Therefore, it seems reasonable to assume that bilingual children acquire vocabulary using the same mechanisms as monolingual children. Even though, their word repertoire in each language might be smaller, parents and professionals need to bear in mind that the size of their vocabulary will vary depending on the level language exposure they receive; influenced by the home, school and social environments. Another language domain subject to language exposure in young bilingual children, is morphosyntax, the process in which children start to use word combinations and produce simple utterances to express themselves. A widespread measure of children’s early morphosyntactic development is “mean length of utterance” (MLU), (Paradis et al, 2011). Such a measure consists of establishing the average length of a child’s utterances, and it is calculated across a number of utterances produced by the child in a spontaneous speech. Most recently researchers have been interested in whether bilingual children’s MLUs augment with age at the same rate as monolinguals. Several studies have been conducted on the topic and they resulted in varied outcomes; showing a similar growth in MLU in bilingual children when they lived in favourable language learning environments, while the MLU appeared to be lower when the bilingual children’s non- dominant language lagged significantly behind their dominant language.