“Pinyin is the Chinese Alphabet”: This is the most common mistake. Chinese is a logographic language; it uses characters (汉字, hànzì) that represent words or concepts, not individual sounds. Pinyin is a phonetic tool to help you pronounce these characters, not the writing system itself. You read characters, but you pronounce Pinyin.
“Pinyin letters sound like English letters”: A dangerous assumption. While many letters are similar (like m, f, s), many are drastically different. For example, “q” sounds like the “ch” in “cheese,” “x” sounds like a hissing “sh,” and “c” sounds like the “ts” in “cats.” You must learn the Pinyin sound chart as its own unique system.
Ignoring Tones: Forgetting the tone mark on a syllable is like misspelling a word in English. The tones are an inseparable part of Pinyin. `mā` (妈, mom), `má` (麻, hemp), `mǎ` (马, horse), and `mà` (骂, to scold) are four completely different words. Pinyin without tones is incomplete and ambiguous.