Focus of nominals is optionally introduced by a highlighter da (homophonous with the equative copula). With da present, the right edge is optionally marked by focus marker sa/so. The background clause is never introduced by a subordinating element, suggesting that it does not have the status of a relative clause.
Source: Kouwenberg 1994: 195
Source: Kouwenberg 1994: 176
Source: Kouwenberg 2007: 42
Source: Kouwenberg 1994: 425
Source: Kouwenberg 1994: 425
Source: Kouwenberg 1994: 426