Well, to be honest, I think there's no best language, every language is good in this world, we are all different, and each language have it's own cultural history and intersting facts. Every language is unique.
But some language are maybe only more useful than others, like Mandarin, English will be 2 dominants language in the modern world. French is the 3rd on the list. I'm a french-canadian, 1 of those 8.5 millions canadians who can speaks french on a total of 34 millions of canadians. For me, french is a beautiful language. French is also a very accurate language, that why all the original version of human right and every UN official's document are in french, it's because french have very accurate word and word arrangement that cannot be misunderstand. The others languages versions of UN's document are translated from the french version.
But french is a hard language to learn, it's harder than English for sure because of all of those verb-subject agreement and all the grammar we have, in fact, french is a modern version of simplified latin. Latin is really hard since you don't have order in which you put the words, you determine the function of the word (i.e. subjet, direct objet, indirect object, adverbial phrase, etc...) by the ending of the word because latin have declension, it's like german but latin is far more complex. Latin have 5 model of declension of nouns (a model of declension is made of 6 different ending for the word which are the nominatif=subject, vocatif=direct call of a person, accusatif=direct object or other kind of object depending on the preposition, genitif=this noun have a role of adjectif or complete another (ie, if i say, the chair of John, John will be at the genitif) and also the genitif's ending determine in which declension is (i.e. Rosae is the 1st), datif which is indirect complement except in some case, and finally ablatif, which is a complement depending of the preposition and there's also a 7th only for city's name..., 2 models for adjective and 5 model of verbs, and you have 12 different commonly use verb tense and all kind of declension for pronouns and things like that... It's very and the grammar is very complex, it's almost a nightmare to learn this when you don't speak french or a latin language like italian or spanish...
