The code for unsetting bit 0 is not done correctly in the code

Currently, the code looks like this:

$bitOp = $db->bitOr( 'lang_mask', -2 );

It should instead, be of this form:

$bitOp = $db->bitAnd( 'lang_mask', ~1 );

In addition the integers are written both as ~1 and -2, that normal form and two's complement form are being mixed inside one function.