Bulgarian seem to nasalize vowels after a nasal consonant:”не”, “ме”. American English and Standard German seem to nasalize vowels in front of the nasal consonant:
This also explains why Americans often say prints instead of prince, and cents instead of sense. The velum closes right after the nasal consonant, resulting in a moment of “n with velum closed” which causes the slight “t” sound before the s. In Bulgarian, we can pronounce “ns” without inserting a t, because our s is actually nasalised, although that cant be heard. American is generally nasalizes more. British English also generally nasalizes before the consonant, but seems like educated speech (RP) doesn’t follow this rule.
Also, the combination “dn” is not possible in English. Apparently, native English speakers have difficulties with this pronunciation when learning languages like Russian.
Source: A CROSS-LINGUISTIC TYPOLOGY OF NASAL HARMONY http://roa.rutgers.edu/files/405-0800/roa-405-walker-3.pdf