Assertion: laughter | /r/CapableOf | appear at about 3.5 to 4 months of age
Facets:
Source sentences:
text: The first laughter appears at about 3.5 to 4 months of age, long before we’re able to speak.
text: The first laughter appears at about 3.5 to 4 months of age, long before we're able to speak.