That's not the same thing. That's an inconsistent mapping of sounds (phonemes) to symbols (and one of the reasons English can be so frustrating to learn). Tones when referring to linguistics are changes in pitch to distinguish words. Given that these differences in pitch (tonemes) are created with the same system (mouth, tongue, lips, vocal chords, &c) as phonemes, you can argue that they're the same, but it's an important enough distinction that linguists find it meaningful.

https://en.wikipedia.org/wiki/Tone_(linguistics)