(extIPA,Teuthonista)indicates that the quality imparted by a diacritic is weaker/lesser than normal.
For example, ⟨ḁ᪽⟩ is a partially devoiced [a], and ⟨ã᪻⟩ a lightly nasalized [a].
(Teuthonista, on a superscript)indicates that a vowel is especially weakened.
For example, ⟨ⁱ⟩ is a weak or fleeting [i]; with ⟨⁽ⁱ⁾⟩, the [i] is scarcely there.
(Teuthonista, on an ascender or descender)indicates that the quality conveyed by the ascender/descender is weakened. Used specifically on the palatal nasal ⟨ŋ᪽⟩.
Parentheses around a doubled diacritic, as ⟨ẽ̃᪻⟩, indicates a degree of intensity intermediate between that of a single and doubled diacritic. Increasing degrees of nasalization of the vowel [e] are written ⟨e ẽ᪻ ẽ ẽ̃᪻ ẽ̃⟩. Similarly, increasing rounding is written ⟨e ë᪻ ë ë̈᪻ ë̈⟩.
Parentheses are sometimes used around orthographic diacritics, as in ⟨ š᪻ ⟩, a sound that may be either s or š, e.g. in a dialect that doesn't distinguish those sounds, or in a reconstruction where the sound is not clear.
The middle parentheses are use for an overstruck diacritic. In the case of ɫ, the result fused to ꬷ.
Doubling the parentheses means the feature is extra weak, e.g. ⟨ ẽ᪼ ⟩.
