TL;DR: Are there any categories for comparing languages based on properties like vowel range and sonority, e.g. the amount of "hard" elements (plosives etc.) or syllable frequency/rate of speech?
I have no background in linguistics except for what I have encountured during language learning, so I am unable to make comparisons with the appropiate jargon. I mean no disrespect whatsoever with the following subjective impressions.
There seems to be general consensus that "soft" or melodic languages are more pleasant to listen to, however vague such a description may be. I have always found this puzzling, as my in-built preference appears to be "harsher" languages with a somewhat limited vowel range, i.e. Spanish over French/Portuguese, Mandarin over Cantonese. Japanese and Korean are fine, while the sound of Dutch or Vietnamese would not entice me to learn them. Russian (+ other Slavic languages) and Arabic strike the perfect balance to my ears.
In addition to a dislike to nasalisation, most of the time it's the presence of diphtong/umlaut-like vowel transitions that make a particular language somewhat unpleasant to me - but that's just what it sounds like to me. While German (okayish) and Finnish (grating) have those, other languages listed don't (in such a prominant way). Cantonese and Mandarin share this feature, too, but in Cantonese, it sounds "strange" to me. Tonality is not the issue, either. What is it that I am perceiving?
I'd like to explore this in more depth, e.g. is there a correlation with one's native language/ an influence of which foreign languages one learns first. Which terms/fields (like lenition, sonority) should I look into further that are related to this issue from a linguistic perspective?