Introduction

The ability to communicate in a second language (L2) or a foreign language (FL) is an output or result of learning a language. To achieve that goal, an input is required. Input can be called as a source of information that can be used to improve communication capabilities. According to Morgan, Meier & Newport (1987), input for language learning must comprise some strands comprehensible words. Language input should also consist of information about how words are classified into syntactic phrase. In addition, input is a crucial element in learning that contributes the important sign in which learners may create linguistic hypotheses. It can be acquired by listening to music, reading newspaper, watching movie and so forth, in the target language (TL) or a language being learned. In everyday life, human brain works like a CPU (Central Processing Unit) on a computer. That is the computer only understands or runs the program already installed in CPU. Likewise, human brain can merely produce words that are already inputted. Therefore, it is impossible for someone to speak using L2 or FL without receiving any input. Among linguists, Krashen is the person who most promotes the significance of input. Instead, his input hypothesis becomes a main reference for researchers who study about the influence of input on the L2 or FL acquisition. Polat (2016) states that input is commonly employed related to the whole language instance in a context that are accessible. Therefore, not all learning resources can be as input, that is the only learning resources which appropriate to learning context. Krashen’s (1981) input hypothesis explicates that language acquisition merely takes place since the input is comprehensible or usually named as comprehensible input (CI). The most important thing in the CI is the concept ‘i+1’. In which the ‘i’ is the language level has been achieved, and the ‘+1’ is the language that is only one step surpasses the level achieved. Moreover, comprehension of the attribute of the determinant features of input is a requirement of the competence to lead input to be comprehensible (Polat, 2016).