Human languages are extraordinarily diverse, and yet there are also systematic commonalities among them. Some of these commonalities can be considered design features of language. These are definitional properties, like regularity and compositionality (the ability to re-use and recombine linguistic units to create new meanings), that all languages share. Other commonalities are perhaps more surprising. For example, almost all languages place adjectives closer to the nouns they modify than numerals (e.g., English `two purple chair’ or Thai, เก้าอี้ ม่วง สอง, literally `chairs purple two’). And when languages form questions by moving a question word, they almost always move it to the left (e.g., English `What did you eat?’ or the Greek equivalent τι έφαγες?). Why do languages share these common features? Where do they come from? In this talk I argue that many of these commonalities–from general design features to highly specific syntactic patterns–are connected to how we learn and create new languages. To support this claim, I highlight recent evidence from laboratory experiments involving miniature artificial spoken and sign languages. These experiments explore how people learn new languages, how they build new meanings in them, and how they create new language systems wholesale. What they show is evidence for the real time emergence of language universals.