The main problem that was solving in this Master‘s thesis – by comparing language skill development of 5-6 years old children from bilingual and monolingual families to see bilingual and monolingual children of that age possibilities and theirs future growing situaton. The study was done at pre-secondary schools of Vilnius and Švenčionys. 100 children from monolingual families and 100 children from bilingual were researched in this Master‘s work. The bilingual families had Lithuanaian and Russian or Polish as a spoken language. This Master‘s thesis conclusion – 5-6 age children from bilingual families have more trained lingual ear, verbal memory and articulation apparatus than those from monolingual families. It was approved statistically true �� p<0,01 by bigger percent of bilingual children results. For example, researching lingual ear – almost 2/3 bilingual children got best award and only 32 percent monolingual the same. The list of literature and appendixes are placed at the end of master’s degree work. 16 pictures, 6 tables illustrate the work, total 57 pages.