This research is a psycholinguistic based research. It examines the lexical semantic features of 12 kindergarten students in International Kids Land Surakarta. This research was conducted in September 2017.

This research aims to know the English quality of students through the analysis of lexical word and grammatical word acquisition and to identify the factors affecting second language acquisition of the students.

The method of the research is descriptive qualitative method which produces data descriptive in the form of words from the observed objects of the research. The research also belongs to ethnographic research since it studies about people in recent setting. Also, the data of the research were analysed qualitatively and inductively based on content analysis.

The result  of data analysis  points  out  that: 1) There are two  findings  of lexical semantic features of kindergarten students in International Kids Land; Lexical Word Findings which  are divided into noun, verb, adjective and adverb; and Grammatical Word Findings that  refer  to  determiner,  preposition,  and  pronoun.  2)  There  are  many  types  of  nouns (common noun, abstract noun, collective noun, compound noun, and material noun); verbs (action verb, transitive verb, intransitive verb, stative verb, and phrasal verb); adjective (coordinate and numbers adjective), and adverb; while determiner (specific and general determiners), preposition (only place preposition) and pronoun.

The conclusions of the research are as follows: 1) Female students acquire more lexical and grammatical words than male students. 2) The quality of English of kindergarten students in International Kids Land is based on the lexical semantic features that they have acquired. 3) There are several factors affecting second language acquisition of kindergarten students especially in critical period such as biological factors, age, characteristic, motivation, and also interaction with family especially parents.