generate questions: Some linguists restrict the double-dot subscript ⟨◌̤⟩ to murmured sonorants, such as vowels and nasals, which are murmured throughout their duration, and use the superscript hook-aitch ⟨◌ʱ⟩ for the breathy-voiced release of obstruents.
What do some linguists restrict the double-dot subscript ⟨◌̤⟩ to? {sep_token} What are, according to the text, murmured for their duration? {sep_token} What uses the ⟨◌ʱ⟩? {sep_token}