ðɪs ʃˈoʊz ðætðə ˌɛndʒˈiː ˈɛn slˈæʃ dʒˈiː tʃˈeɪndʒ ɪz ʌv fˈɛɹli ɹˈiːsənt dˈeɪt; lˈæŋ, nˈaʊ lˈæɡ, ɪz aɪdˈɛntɪkəl tə ðə ɡˈɪzɹə lˈæŋ ʌvðə sˈeɪm mˈiːnɪŋ.
This shows that the 'ng' > 'n'/'g' change is of fairly recent date; lang, now lag, is identical to the Gizrra lang of the same meaning.