In English, the digraph often represents the velar nasal, as in long lɒŋ and nothing ˈnʌθɪŋ. In other cases, it represents a sequence of the velar nasal followed by the voiced velar stop, as in longer ˈlɒŋɡər, which had been the original pronunciation of the digraph up until Early Modern English when the g sound was lost in most words, giving ŋ a phonemic status in English. Another pronunciation is ndʒ, as in angel ˈeɪndʒəl and one pronunciation of longevity lɒnˈdʒɛvɪti (alternatively pronounced with ŋdʒ, lɒŋˈdʒɛvɪti, by analogy with long).
In Old English and Middle English, any ng sequence stood for two sounds: the velar nasal ŋ followed by the voiced velar stop ɡ. The velar nasal did not have a phonemic status, being a mere allophone of /n/, as in Spanish or Italian (or as in Modern Standard English in words such as Bengali or Vancouver, where there is a free variation between an alveolar nasal and a velar nasal). From Early Modern English onwards, the oral stop ɡ ceased to be pronounced in educated London speech, giving /ŋ/ a phonemic status according to some analyses (some scholars still reject it as a phoneme and consider it to be a realization of the underlying /nɡ/). This is termed NG coalescence by John C. Wells. There are certain varieties of English where the ng-coalescence did not take place, such as those spoken in the western part of the English Midlands and the middle north of England, such as Brummie, Mancunian and Scouse. Since the underlying form in those dialects is /nɡ/ (i.e. the speakers perceive n and ŋ to be the same sound), the g is literally dropped for those speakers who use [ɪn] etc. for -ing.
G-dropping in English is a linguistic variable by which what in standard English is ɪŋ is realized as [ɪn], [ɨ̞n] or [ən] in unstressed morpheme-final (often word-final) syllables. In most varieties of English, G-dropping does not involve actually omitting a g sound; there is no g sound present in the standard pronunciation to be dropped.