and Cho (2011), at the early stages of language acquisition, children ask yes-no questions by rising intonation alone as they develop awareness to auxiliary verbs only at a later stage. When auxiliary verbs make their appearance, it takes children a few months before they are able to use inversion in yes-no questions. The development of WH- questions occurs between the ages of two and four, when children acquire auxiliary verbs that then leads to the ability to use inversion in questions. However, some children find inversion easier in yes-no questions than in WH- questions, since the position of both the WH- word and the auxiliary verb must change (e.g., "You are going where?" instead of "Where are you going?"). Morphological development Morphological structures development occurs over a period of several years. Before language is acquired, children lack any use of morphological structures. The morphological structures that children acquire during their childhood, and even up to the early school years, are: determiners (a, the), -ing inflection, plural –s, auxiliary be, possessive –s, third person singular –s, past tense –ed). When children start using them they tend to overgeneralize the rules and project them upon all the words in the language, including irregulars. For example: if a child knows the –ed (past tense) there is a possibility that they'll say "I eated" (man-mans cat-cats). These errors result from overgeneralization of rules. This overgeneralization is very noticeable, in fact, children do that in less than 25 percent of the time at any point before reducing that percentage. Then they improve their mastery, which can be tested in various ways, such as the "wug test" (Berko, 1958). Children often figure out quickly frequent irregular verbs, such as go and buy rather than less common ones, such as win. This suggests that children must hear the word several hundred times before they are able to use it correctly. This development of bound morphemes is similar in order among children, for example: -ing is acquired before the article the. However, parents tend to use a different order while speaking to their kids, for example, parents use the article 'the' more frequently than -ing. Meaning, other factors determine the order of acquisition, such as: Morphemes that come at the end of an utterance are remembered better. Children seem to remember morphemes such as –ing better because they contain their own syllables rather than single consonant morpheme, such