Mandarin Chinese is often used as an example of a tonal language (one where the meaning of a word depends not only on its articulation but also on its pitch contour).
However, going by what I've read, tone does not actually appear to be vital in Mandarin:
- When singing in Mandarin, the pitch contour of the lyrics follows that of the melody of the song, even when this conflicts with the pitch contour normally expected for a given syllable. For a language in which tone is truly phonemic, this tone-scrambling would render the lyrics unintelligible unless the lyrics are carefully chosen to match pitch contours with the music. Yet Mandarin remains fully-comprehensible even when the pitch contour of the music is completely wrong for that of the syllables making up the lyrics, as detailed in the answers to this LingSE question as well as in this Reddit thread involving several native speakers of Mandarin.1
- Additionally, Mandarin remains fully-intelligible when written in a script with no provision for tone marking, as can be seen in the xiao'erjing style of writing, which uses vocalized Arabic script to write Mandarin. If tone were phonemic for Mandarin, one would expect that writing the language in a script incapable of indicating the tones being used would leave the reader with too little information to determine what was written - which is evidently not the case with Mandarin.
Given the above, is Mandarin actually a tonal language, as opposed to merely one with unusually-highly-pervasive intonation?
1: By way of contrast, singing in Cantonese does apparently require that the lyrics be chosen to match the music's pitch contour in order to avoid ending up with gibberish.