This belongs to which family in English?

Question

Therefore, unfortunately, nevertheless, Besides this, etc. all this is conjuctions?

Answer 1

For some reason they count as adverbs.

Answer 2

They are adverbs.

An adverb modifis a verb, an adjective, another adverb, a phrase, or a clause. An adverb indicates manner, time, place, cause, or degree and answers questions such as:
"how," "when," "where," "how much".

While some adverbs can be identified by their characteristic "ly" suffix, most of them must be identified by untangling the grammatical relationships within the sentence or clause as a whole. Unlike an adjective, an adverb can be found in various places within the sentence. Example:

The seamstress QUICKLY made the mourning clothes

The BOLDLY-spoken words would return to haunt the rebel

Conjunctive adverbs can be use to join two clauses together:
"also," "consequently," "finally," "furthermore," "hence," "however," "incidentally," "indeed," "instead," "likewise," "meanwhile," "nevertheless," "next," "nonetheless," "otherwise," "still," "then," "therefore," and "thus." Example:

The government has cut university budgets; CONSEQUENTLY, class sizes have been increased.

He did not have all the ingredients the recipe called for; THEREFORE, he decided to make something else.

The report recommended several changes to the ways the corporation accounted for donations; FURTHERMORE, it suggested that a new auditor be appointed immediately.

The crowd waited patiently for three hours; FINALLY, the doors to the stadium were opened.

Batman and Robin fruitlessly searched the building; INDEED, the Joker had escaped through a secret door in the basement.

Answer 3

Yes these are conjunctions. Examples:
1. I think THEREFORE I am. (therefore, joins the two clauses)
2. He quit unfortunately, nevertheless the show will go on.
(adverb) (joins the show will go.. and he quit...)
3. I don't need that red coat besides I already have one.
(joins the 1st sentence with the 2nd)