x1 (text) is written in a dialect where selbri in every bridi-tail is assumed to have {so'o'o'oi} applied to it
Implicit so'o'o'oi is not applied to other selbri like direct children of sumti and selbri rules, mex-operator, operand-3, free, tense-modal. 'sei onga'/'sei na onga' is a method of switching to/from VSO-like style in Lojban. See also colzu'e.