How to pronunce "eng"
If I understand your question correctly, the answer is no, Mandarin -en is not part of -eng, just like English &quot;sin&quot; is not part of &quot;sing&quot;.
Even though &quot;ng&quot; is written with two letters in both Mandarin and English, there is only one sound: [ŋ]. That's the sound at the end of &quot;sing&quot; in English. Pinyin -n is close to the sound at the end of &quot;sin&quot; in English.
I suggest that you play around with these words in English a bit until you realise that &quot;ng&quot; is actually one sound, even if it's written with two letters. The situation is analogous to -n and -ng in Mandarin.
The vowel is the central vowel [ə] in both cases, which is the most common sound in human speech. It's the same as &quot;a&quot; or &quot;the&quot; in English (although it can vary by English dialect, of course).