Lesson 2.8 no desu ga

Minna san, konnichiwa. Watashi wa Jason desu. Hajimemashite! Yoroshiku onegaishimasu!
Zu~tto mai ni nihongo wo yoku benkyou shimashita ga sore wa nan nen mai desu. Takusan wasureteshimaimashita! Ima wa mo ikkai yomeru to kikoeru to shaberu you ni benkyou ni wa ganbatteimasu yo ne! Dakedo toki doki watashi ga oboiteiru nihongo to rocketo nihongo wa sukoshi chigaimasu.
Soretomo, Lesson 2.8 ni wa, "no desu ga" to iuu no wa, so no mama ni "no desu Ga" de hanashiteimasu. Sore wa machigainai desu ga watashi ga oshietemoratta koto wa, hanasu toki ni, kono "no desu ga" kotoba wa "no desu Nga" de hansuto mo chotto honto no nihongo de kikoeru koto to omoimashita.
Betsu no hito wa, kono koto ni dou omoimasuka?

Ｊａｓｏｎ！こんにちは、
私も、もっと前、日本語を勉強しました。
＊のですんが＊と聞いたことがないけれど、＊んですが＊と良く聞きました。
たとえば、行くんですが、遅れます。

セシリア
 

Seshiria (Cecilia?) san,

Konnichiwa! Nihongo ga boku yori yoku dekirusou desu yo ne?!  Watashi ga kaita koto wo yonde kurete arigatou.
Watashi ga "no desu ga" to "n desu ga" wo daitai wakaru to omoimasu kedo hanashitakatta koto wa so no you jya nai to omoimasu.  Nihongo de setsumon wo suro koto wa chotto muzukashi desu.

What I was trying to say, was that I recall one of my instructors teaching us that while it is not incorrect to clearly pronounce the glottal g in Ga following in phrases such as "no desu ga" that we should not be surprised to hear a softening of the articulation with a slight "n" preceding the g in ga. It was not a function of grammar, but rather a function of speech. If you focus on how your mouth and tongue have to work in transition from su to ga, versus how it is slightly smoother with an almost imperceptible n between the su and ga, it will at least emphasize my thought. What I wondered, since the recorded lessons were very clearly distinct glottal G's on the ga, was whether anyone else was familiar with this idea and whether it was perhaps a regional thing. I know that when I studied in Nagasaki, there were a ton of local speech habits that would likely not be found further north.
Hayatun, taisetsu na koto jya nakute so no mama no benkyou suru toki no aida no kangai desu. Mo ikkai, yonda to (response) wo shite kurete, arigatou!
Kore kara, yoroshiku onegaishimasu, Seshiria san!

こんにちは (Konnichiwa) azenphish and セシリア,

ご質問をありがとうございます。 (Goshitsumon o arigatō gozaimasu.) Thank you for your question!

が (Ga) can be pronounced as "ga," with a glottal "g" sound, or "nga," with a nasal "g" sound. Both of these are perfectly correct! However the nasal "g" sound seems to be more of a dialect thing, and is more common amongst people from the Kanto region. You may also hear it used by radio broadcasters or news hosts. 
It is also more commonly used by older Japanese people. Younger people tend to opt for the glottal "ga" sound. 

I hope this helped! Please let me know if you have any more questions!

勉強を頑張って下さい！ (Benkyō o ganbatte kudasai!)