i am learning chinese.i have completed just few levels when i found out that same alphabet is used twice and with different sound and meaning. it makes my work difficult.
It's hard to know what you mean without examples, but a problem that I had for a while when I started was that some vowels in pinyin are dependent on the initial consonant.
For example, i is a long sound when it comes after certain sounds like in xi, qi, ji, bi, di, ni, pi, yi but short after others, like in shi, chi, zhi, ci, zi, ri. Similarly, the u sound is fronted after alveolo-palatal initials, so xu, qu, jun are basically shorthand for xü, qü, jün.
Hope this helps.