Let's elevate this question from a party game of posturing and flattery/pandering, shall we?

I'll stick to spoken form and ignore the visual written form. The two are mostly unrelated questions. I'll ignore literary content entirely because I think that is an independent question about the culture, not the language per se (i.e., you can have ugly culture/literature in a beautiful sounding/looking language form, and vice versa).

This question has a very peculiar problem: those who are fluent enough to think in a language are least qualified to assess its sound for aesthetics. This is because those who understand a given language are hearing not the sound of the language itself, but meanings that convey powerful cultural identity reflections. They are hearing stories, lyrics, history, friendships, family histories, their own sense of otherness or belonging, and the voices of personal angels and demons. They literally cannot *hear* the sound itself. They hear their own relationship with the associated culture and are 80% deaf to the sensory experience. This is not an insider/outsider perception problem. It is a physical disability problem. Acquiring fluency in a language is a process of losing some capacities, not just gain. If you don't hear near-pure gibberish, I don't take your opinion of a language's beauty as credible. A rare instance of outsiders being more credible on a subject than insiders.

But there is an interesting variant of this question that can create a meaningful debate on aesthetics: what languages that you aren't fluent enough to think in do you consider beautiful? That minimum-distance restriction allows me to comment on languages other than English, Hindi and Kannada.

Or to back up a bit, what do you even *hear* sensory-texturally, and what is your emotional reaction? That way you can at least explain what you find beautiful or not. I'll use some examples I've heard a lot of, but don't understand. Treat these like descriptions of wine tastings: personal and idiosyncratic. YMMV.

Bengali: smooth, oily chattering with lots of O and SH sounds when spoken, doleful moaning when sung. I find both quite annoying (Rabindrasangeet makes me want to stab a pencil in my ear, I've rarely met non-Bengalis who like it). Telugu evokes a similar reaction (I am not a Telugu speaker, despite my name). Don't enjoy the sound of either. Speakers of both seem inordinately fond of the sound they hear, relative to outsiders, who (anecdotally) find them *less* pleasant than other languages (as you'll see in my own list below... I like almost all the remaining languages better than Bengali and Telugu).

Marathi: sounds guttural and hick with a lot of open and airy noises, and A, Z and H sounds. It sounds relaxed, good-humored and laid back. I like it. Sort of a Larry the Cable Guy sound.

Punjabi, Tamil, Japanese: sharp, vigorous, martial and clearly enunciated, very bold and punchy. Music in the first two languages makes me cheerful and peppy. Street conversations energize me. Tamil is probably the language that allows the most effective "angry thundering" that I've heard. I suspect you can boom indefinitely in Tamil, where in other languages you'd have to scream and exhaust your voice in minutes.

Arabic and Italian: sound very emotionally rich. They exhibit the most emotional range, from measured, high status, soothing tones that reassure to excited childlike chattering that annoys. Since I am not a very emotional person, they make me feel detached and distant from whatever is going on. They both sound very extroverted, with a lower thought-to-words ratio, as though the languages are more for communication in complex interpersonal ways than private thought. My reaction is "clearly many will find them beautiful, but not really for me."

All tonal east Asian languages: they REALLY throw me off in a very unsettling way, like fingernails on a chalkboard. In non-tonal languages, tones convey emotion and go with facial expressions. In tonal languages, speed and sputtering/hissing seem to do the emotional work. The tones sound whiny or pleading a lot of the time, but facial expressions seem to be conducting a different conversation. It is the most cryptic and alien sound for me, like I am hearing the internal sounds of a Borg cube. Scares me a bit.

Korean: the language seems to be bimodal. There is a cute mode full of oohs, aahs, childlike twittering and simpering, and a second vigorous, martial mode sort of like the Punjabi/Tamil/Japanese triad (a bit more harsh and raspy though). I dislike the former, but like the latter.

German: sing-song and high pitched when I unconsciously expect staccato baritone barking. Too many WW II movies I guess. Very pleasant, direct and immediately engaging, like a smooth beer. Friendly, down-to-earth, sort of like Marathi, but in a different way. But there is also a soft/whispery way it seems to be spoken sometimes (Christoph Waltz) that I like even better.

French: the language always sounds to me like the speaker is thinking faster than words are able to get out. So it sounds searching, thoughtful, tentative and slightly argumentative, with a questioning lilt to everything. Feels very personal, intimate and engaging, almost uncomfortably so. But paradoxically there is also a curious subtext of introversion, reserve and watchful caution. French silences sound like scrutiny and observation. Most other languages, silences sound more like boredom. It is the most cerebral/intellectual sounding language to me. It sounds like it is used more for thinking and writing than speaking. The music sounds wonderfully lyrical, like very subtle thoughts are being expressed. Linguists may group French and Italian together, but they sound like very different personalities to me. Also most unfamiliar languages (including for me, all the rest in this list) sound "stupider" and more childlike to me (this is a common perceptual bias I believe, with no actual basis in fact -- it's sort of like the law of visual perspective, distant things appearing smaller) than ones I speak, but French goes the other way. At the risk of encouraging French glee, French sounds smarter than languages I speak, and I get the feeling I'd be smarter if I could speak it, and think thoughts I can't now.

Spanish: oddly enough, though I hear a lot of it, it doesn't register aesthetically much. The spoken form sounds like a mix of intensely pragmatic market-transactional, almost like computer code, and consciously added exaggerated melodrama. Like very logical people making an overwrought effort to appear more emotional than they are. In the music, the instruments overwhelm the lyrical quality for me, so I have no opinion on the language component. I should add that arthouse-movie Spanish sounds closer to French to me than the everyday and TV varieties.

Russian: haven't heard enough, but the Russian English accent is probably the pleasantest way English can be spoken, as far as I am concerned. They seem to somehow soften the sharp sounds and add gravelly texture to the smooth sounds, making the whole more pleasant, like a glossy image converted to matte. I prefer it to Native English accents (UK and US). I'd speak that way if I could, but sadly I have probably the second worst possible English accent (generic Indian). I'll cleverly not reveal my candidate for worst English accent.