What are Tones in Mandarin Chinese?
Many Chinese words have the same Pinyin letters (Latin letters) but depending on how each syllable is pronounced (i.e. the tone which means the pitch (soprano and baritone would be extremes) and the volume) can totally change the meaning of the word. An accent above a Pinyin letter tells a person how the syllable is to be pronounced.

For example:
xióngmāo means PANDA
but
xiōngmáo means CHEST HAIR
or
dā means to put up
dá means to answer
dă means to hit
dà means big
or
mā means mother
mă means horse
Tones are important, don't ignore them.