First Tone: ˉ
This tone is designated by a straight line over the vowel (mā) and is pronounced flat and high like the "ma" in Obama.
Second Tone: ´
This tone's symbol is an upward slant from right to left over the vowel (má) and begins in the mid-tone, then rises to a high tone, as if asking a question.
Third Tone: ˇ
This tone has a V-shape over the vowel (mă) and starts low then goes even lower before it rises to a high tone. This is also known as falling-rising tone.
It's as if your voice is tracing a check mark, starting at the middle, then lower then high.
Fourth Tone: `
This tone is represented by a downward slant from right to left over the vowel (mà)and begins in a high tone but falls sharply with a strong guttural tone at the end like you are mad.
This tone is also known as the neutral tone. Has no symbol over the vowel (ma) or is sometimes preceded with a dot (‧ma) and is pronounced flatly without any intonation. Sometimes it's just slightly softer than first tone.