Readers paying attention to the Kalash thread will notice Catholicgauze has encountered pro-Albanians who among other things claim 1) Alexander the Great was Albanian 2) Greeks and others are just Albanian posers 3) Albanians are the descendants of Atlantis and 4) Kalash are Albanians (I think, they have not been very clear). There evidence you ask? Some Albanian and Kalash words are similar! When Catholicgauze read that I slapped my head. That's because both Kalash and Albanian are Indo-European languages.
Under the leading theory, around the 4th millennium BC, the Kurgan people began to spread from out of the Pontic-Caspian steppe. The language of the Kurgan is thought to be the first Indo-European language. The vast dispersal was made possible because of the Kurgans use of horses. The Kurgan reach (and probable proto-Catholicgauzes) ranged from Western Europe to India. Today languages probably based from the Kurgan include English, German, French, Latin, Greek, Slavic, Farsi, Hindi, and many more.
As time progressed words changed but simpler ones continue to share similarities. Some words continue to remain almost universal between Indo-European languages. Just think of possibly the most common conversation in the world: "Mom? No!" "Mama? Non!" "Madre? No!" "Mutter? Nein!" "Mama? Nyet!" and so on and so on.
The Age of Colonization and then Imperialism allowed Indo-European languages (in particular English, Spanish, French, and Portuguese) to spread throughout the world. Today Indo-European Languages are either the official or an official secondary language in most countries. Seven of the top ten languages spoken by native speakers today are Indo-European.
The main contender to Indo-European is the Semitic language family of Arabic (spread via Islamic conquest), Hebrew (contained to the Jewish race) and a few other small religious languages such as Syriac (mostly in Eastern Christianity). Semitic languages are deeply interwinded with the religion of the respected speakers.
Niger-Congo is another competitor and it comprises most of sub-Saharan Africa. Many places which have a Niger-Congo language also recognize an Indo-European language due to the influence of colonization.
Other language families like Sino-Tibetan (Chinese, et al) and Japonic (Japanese and a few regional languages in Japan) are limited to one or a few national groups. While there was major European interaction with these groups, East Asia for the most part was able to adopt cultural advancements while still retaining their own identity.