What is "metatony"

In linguistics, metatony refers to the change of nature of accent (its intonation, or tone), usually within the same syllable. When the accent also changes its syllable, the process is called metataxis. Metataxis can also be analyzed as a combination of accent movement and metatony. The term is usually used when referring to accentual developments in the history of Baltic and Slavic languages which exhibited numerous such developments, representing the accentual equivalent of sound change.