Roughly 40% of people alive today speak a language derived from Proto-Indo-European as their primary parlance. The original speakers of PIE are hypothesized to have been Caspian Steppe herders about 6000 years ago. This grandmother tongue spread through some conquests, but mostly through trade, migration, and prestige. The Hittites in Anatolia spoke an early offshoot, and ultimately hundreds of daughter and granddaughter languages branched between the Himalayan Mountains and the Scottish Highlands. Comparing commonly used words across languages, many ancient words can be reconstructed. The names of rivers and other landmarks can be used to research dialectical spread and changes. Goods, industry, stories, rituals, and other cultural behaviors also spread alongside vernacular.