Translation:I call their names, i.e. Tono and Andi.
It means "that is...". You'd say it before clarifying a statement, but it's used more in writing than spoken dialogue. Here's an example I found on Wiktionary:
"The three U.S. states on the west coast (i.e., Washington, Oregon, and California) have mild seasonal variations in temperature (i.e., warm winters and cool summers)."
In Arabic we also use it much, we say 'yaini'. It means 'that means', but you can translate it as: that is to say..., I mean..., for example..., namely...
We use it a lot. The Indonesian 'yaitu' seems comparative to me. Every sentence with yaitu until now I could easily interchange it with the Arabic 'yaini'.