How Multi-Word Phrases Become Single Words
Languages constantly shrink phrases into single words through a process called univerbation. What once took several distinct parts is eventually fused into one permanent term as speech evolves.
This process happens when speakers repeatedly use common phrases until they become inseparable units. For example, the word already started as the phrase all ready, eventually condensing over centuries of usage. It is a hidden linguistic shortcut that creates much of our modern vocabulary. This natural evolution shows that language is a living, shifting tool that prefers efficiency above all else.
Source: Univerbation