I'm running into a type mismatch error with the last line. Any ideas?

```
Dim language As String

Dim langOps(0 To 2) As String

If CheckBox10.Value = True Then
    langOps(0) = CheckBox10.Caption
End If

If CheckBox15.Value = True Then
    langOps(1) = CheckBox15.Caption
End If

If CheckBox29.Value = True Then
    langOps(2) = CheckBox29.Caption
End If

language = Join(langOps, [, ])

```