How to check the word "harbinger"?
The word Harbinger turns out to be a masculine noun and second declension in which we select the zero ending: Harbinger-Harbinger-Harbinger.
The stress in it falls on the second syllable: precursor.
The root of the word turns out to be the morpheme WEST-: News-Izvestia
Note that this word contains an unpronounceable consonant T in the STN combination, and the word itself can be mistakenly written as a tag.
The prefix PRID does not exist, so we write the vowel E in it, you can check the consonant T with the words weight-weight. You cannot write the suffix NIK in any other way, the last consonant K can be checked, just in case, with the word harbingers.
In the word FOREIGNER there is a prefix PRE-, the spelling of which must be remembered, since there are no other variants of its spelling: pre-jubilee, predecessor, foothill.
At the root of WEST, we write an unpronounceable consonant T, since the test words are news, news, news, where the unpronounceable consonant is clearly heard.