Here's a breakdown:
* Present tense: The Proto-Germanic present tense forms of "to be" derive from two separate roots:
* *wesaną: This root, meaning "to dwell," gave rise to the forms *wesu, *wis, *wesi, *wesum, *wesuth, *wesiþ. These forms are the basis for the English "is," "am," and "are" (though these forms have undergone significant changes through Old English and Middle English).
* *bēun: This root, meaning "to exist," gave rise to the form *bēu, which was likely used for the third-person singular (he/she/it is).
* Past tense: The Proto-Germanic past tense forms of "to be" also came from two roots:
* *wesaną: This same root contributed the forms *was, *wēsun, *wēstum, *wēsut, *wēsun. These forms are the basis for the English "was," "were," and "were."
* *bēun: This root contributed the forms *bēu and *bēun, likely used for the third-person singular and plural (he/she/it was, they were).
Merging:
It's important to note that these roots were not always distinct in Proto-Germanic. Over time, some forms merged, and the meaning of "to be" became increasingly complex. For instance, the third-person singular form *bēu could have been used for both present and past tense.
Evolution:
The Proto-Germanic forms of "to be" continued to evolve in the individual Germanic languages. In Old English, for example, the forms of "to be" were even more numerous and irregular. It wasn't until Middle English that the forms began to resemble their modern English counterparts.
In summary, the Proto-Germanic origins of "to be" are complex and reflect the evolution of the language over time. While multiple roots were involved, the primary ones were "*wesaną" (to dwell) and "*bēun" (to exist), which gave rise to the various forms of the verb in Proto-Germanic and subsequently in its daughter languages like English.