Languages that communicate efficiently will avoid sending information that is redundant with information provided in the context.
lˈæŋɡwɪdʒᵻz ðæt kəmjˈuːnᵻkˌeɪt ɪfˈɪʃəntli wɪl ɐvˈɔɪd sˈɛndɪŋ ˌɪnfɚmˈeɪʃən ðæt ɪz ɹᵻdˈʌndənt wɪð ˌɪnfɚmˈeɪʃən pɹəvˈaɪdᵻd ɪnðə kˈɑːntɛkst.