ESPERANTO - the inventor paid his dues
Ludwig Lazarus Zamenhof (born Leyzer Leyvi Zamengov in 1859 in Bialystok, Poland) spoke Russian, Polish, and Yiddish as a child. He later learned a number of other languages. The languages of his childhood are highly inflected, and when he came to invent Esperanto, he could not stand to be without just one. So direct objects (accusative case) take a suffix "n". Aside from that, there is extensive use of suffixes and prefixes to carry all the other features of grammar in a quite regular way.
He felt that Italian was the most beautiful language to the ear, so the sound of Esperanto tends toward that sound.
Vocabulary was stolen/borrowed from various European languages, both Latin-based and English-based.
Back when I started programming, I also studied this language briefly, as an alternative form of code-talking. How very geeky!