The silent "g" in English occurs in words where "g" is not pronounced, usually before "n" at the beginning or middle of a word. 
This spelling convention has historical roots in Old English and Latin. 
Originally, the "g" was pronounced, but over time, its pronunciation was dropped while the spelling was retained.

Inglish drops the silent "g" from words of Old English origin, but often keeps them for words of French and Latin origin. 
-ign, -égn, and -aign are common in Inglish.

Examples:
    Gnaw: From Old English "gnagan"
    Gnome: From Latin "gnomus," influenced by Greek "γνώμη" (gnome), meaning "thought" or "judgment."
    Sign: From Latin "signum"
    Design: From Latin "designare"
    Gnash: From Middle English "gnaschen"
    Gnat: From Old English "gnæt"

Inglish:
    naɯ, naue
    nome
    sign(e
    design(e
    nash(e
    nàt

Inglish re-adds -g- in some English words were a -g- existed in the Latin.

Latin: "com-" (together) + "plangere" (to lament) = "complangere"
Old French: "complaindre"
Middle English: "complainen"
Modern English: "complain", "complaint", "complainant"
Inglish: "complaigne", "complaignt", "complaignant"

Latin: "campus" (field)
Late Latin: "campania" (level country, field)
Old French: "campagne" (open country, field)
Modern English: "campaign"
Inglish: "campaign"

Latin: "campus" (field)
Late Latin: "campania" (open country, plain)
Old French: "Champagne" (region in northeastern France)
Modern English: "champagne" (sparkling wine from the Champagne region of France)
Inglish: "çampaign"

And some words just maintain a more Latin aesthetic:

Latin: "regnum"
Old French: "reigne"
Modern French: "règne"
Middle English: "regne"
Modern English: "reign", "regnant"
Inglish: "régn(e", "regnant"

-ign is pronounced as "aɪn"
-aign and -égn are pronounced as "eɪn"

The -g- is pronounced when suffixes are added to -ign and -égn.

sign(e /saɪn/, signaȶure /ˈsɪɡ.nə.tʃər/
design(e /də'zaɪn/, designaiçon /ˌdɛz.ɪɡˈneɪ.ʃən/
régn(e /reɪn/, regnant /ˈrɛɡ.nənt/