"Chant" is a European concept: http://en.wikipedia.org/wiki/Chant
Chant (from French chanter) is the rhythmic speaking or singing of words or sounds, often primarily on one or two pitches called reciting tones. Chants may range from a simple melody involving a limited set of notes to highly complex musical structures, often including a great deal of repetition of musical subphrases, such as Great Responsories and Offertories of Gregorian chant. Chant may be considered speech, music, or a heightened or stylized form of speech. In the later Middle Ages some religious chant evolved into song (forming one of the roots of later Western music).
Traditional Pali chants certainly use rhythm.
See: http://www.accesstoinsight.org/lib/auth ... #pronounce
The meters of Pāli poetry consists of various patterns of full-length syllables alternating with half-length syllables.
There are some variations that I am aware of:
1. The native language of the speaker has an effect. For example, Thai speakers read Pali transliterated into Thai script, and they generally use the appropriate tone, just as they would if speaking Thai... This could hardly be criticised, it's just the way the language works, but it means that they sound different from Burmese or Sri Lankan reciters.
2. The western Ajahn Chah sangha has developed a style for English chanting that sound to me like an adaption of Gregorian chanting http://forestsanghapublications.org/vie ... 26&ref=deb
using tone marks to give a three-tone system. They also use the tone marks on the Pali, which at a quick glance, is based on the most obvious Thai tonal inflections. Western Ajahn Chah Sangha recording that I've listened to (and sometimes followed along with at meditation groups) seem to emphasise the tonal aspects more, and the rhythmic aspects less, than the Thai monastics I chant with. However, the variation between Thai and Western Ajahn Chah chanting is smaller than Thai to Burmese, for example.