Arguments like language or safesearch are not passed to the params[..] when paging or time-range is not supported by the engine.

If you are talking about this condition:

if search_query.pageno > 1 and not self.engine.paging: 
    return None

-->

If user query is not asking for the page one = page two, three, ... (1) and the engine doesn't support paging (2) then the engine won't get the query (3).

• (1) search_query.pageno > 1
• (2) not self.engine.paging
• (3) return None : in the following code fragment, continue means the query is skipped for this engine:

  searxng/searx/search/__init__.py

  Lines 95 to 98 in 50ec821

  	# set default request parameters
  	request_params = processor.get_params(self.search_query, engineref.category)
  	if request_params is None:
  	continue

Same for time_range_support : if a specific date range is asked and the engine does not support time range, then the engine don't get the query.