adjective (a)

• employing variations in pitch to distinguish meanings of otherwise similar words(adj.pert)

  Example:
  Chinese is a tonal language.
  

  Synonym:
  tonic
  

  source: wordnet30
• having tonality; i.e. tones and chords organized in relation to one tone such as a keynote or tonic(adj.all)

  Antonym:
  atonal, unkeyed
  

  source: wordnet30