CHAT2PRAAT – CHAT to Praat TextGrid

Status: Current

Purpose

Converts CHAT files to Praat TextGrid format for acoustic/phonetic analysis. Each speaker becomes a separate interval tier, with timed utterances mapped to intervals.

This is the reverse of PRAAT2CHAT. Both conversions are implemented in the same module (praat2chat).

Usage

chatter clan chat2praat file.cha
chatter clan chat2praat file.cha -o output.TextGrid

Behavior

• Each speaker in the CHAT file becomes a separate interval tier
• Only timed utterances (those with bullet timing) are included
• Timing bullets are converted from milliseconds to seconds
• Speaker codes become tier names
• Utterance text is extracted with annotations stripped
• If no timed utterances exist, an empty string is returned

Output format

Produces standard Praat TextGrid long format:

File type = "ooTextFile"
Object class = "TextGrid"

xmin = 0
xmax = 5.042652
tiers? <exists>
size = 2
item []:
    item [1]:
        class = "IntervalTier"
        name = "CHI"
        ...

Differences from CLAN

• Uses the typed AST to extract timing and text, rather than string scanning
• Bidirectional conversion in one module (CLAN has separate praat2chat and chat2praat binaries)
• Deterministic speaker tier ordering via BTreeMap