SEATTLE — After about a year working at Lionbridge Technologies on Microsoft’s campus, Marilyse Benyakar started asking questions.

Why did Lionbridge, hired by Microsoft to vet the content of Windows tablet applications, not offer paid time off or sick days? How long could Benyakar and other so-called temporary workers remain that way?

Those questions ultimately resulted in something exceedingly rare in the technology industry: a group of employees voted to form a union.

It began at a small gathering of employees who met with Lionbridge managers in the summer of 2013. The employees were told to be frank, and Benyakar says she asked whether she and other employees could get additional pay and benefits. Microsoft managers appeared happy with their work, she said.