Is there support for claiming -gn- was pronounced as /ŋ/ in classical Latin?

1. How do we know how classical Latin was pronounced?
2. How is ŋ pronounced?
3. Where ŋ Cannot occur in a word?
4. How is the C pronounced in classical Latin?

How do we know how classical Latin was pronounced?

Knowledge of how Latin was pronounced comes from Roman grammar books, common misspellings by Romans, transcriptions into other ancient languages, and from how pronunciation has evolved in derived Romance languages.

How is ŋ pronounced?

To make the /ŋ/ sound:

Lift the back of your tongue (like you're making a “k” sound) and place it against the soft palate at the back of your mouth. Vibrate your vocal cords. Do not let any air leave through your mouth; it should all leave through your nose.

Where ŋ Cannot occur in a word?

#C Of consonants ŋ does not occur at the beginning of words at all.

How is the C pronounced in classical Latin?

c is pronounced k: cantus (kahn-toos). cc before e, i, y, ae, oe is pronounced tch: ecce (eht-cheh). ch is pronounced k: cherubim (keh-roo-beem). g before e, i, y, ae, oe is soft (as in gel): genitum (jeh-nee-toom); otherwise, g is hard (as in go): gaudeamus (gah-oo-deh-ah-moos).