Ngôn ngữ đã tồn tại bao lâu? (How Old IS Language?)

US /spɪˈsɪfɪk/

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UK /spəˈsɪfɪk/

US /ˈkɑɡnɪtɪv/

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UK /ˈkɒgnətɪv/

US /ɪˈvɛntʃuəli/

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UK /ɪˈventʃuəli/

US /əˈsum/

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UK /ə'sju:m/