What are adverbs?

Some articles on adverbs:

Basque Grammar - Noun Phrase - Declension - Local Cases With Adverbs
... the primary forms) are incorporated into the place adverbs, giving the following (partly irregular) forms Place adverbs Demonstrative Interrogative 'where?' 'here' 'there (near)' 'there ...
Erya - Contents
... Chapter Chinese Pinyin Translation Subject 1 釋詁 Shigu Explaining the Old verbs, adjectives, adverbs, grammatical particles 2 釋言 Shiyan Explaining Words verbs, adjectives, adverbs 3 釋訓 Shixun Explaining Instructions adjectives, adverbs, mostly with reduplication 4 釋親 Shiqin Explaining Relatives kinship, marriage 5 釋宮 Shigong Explaining Dwellings architecture, engineering 6 釋器 Shiqi Explaining Utensils tools, weapons, clothing, and their uses 7 釋樂 Shiyue Explaining Music music, musical instruments, dancing 8 釋天 Shitian Explaining Heaven astronomy, astrology, meteorology, calendar 9 釋地 Shidi Explaining Earth geography, geology, some regional lore 10 釋丘 Shiqiu Explaining Hills topography, Fengshui terms 11 釋山 Shishan Explaining Mountains mountains, famous mountains 12 釋水 Shishui Explaining Rivers rivers, navigation, irrigation, boating 13 釋草 Shicao Explaining Plants grasses, herbs, grains, vegetables 14 釋木 Shimu Explaining Trees trees, shrubs, some botanical terms 15 釋蟲 Shichong Explaining Insects insects, spiders, reptiles, etc. 16 釋魚 Shiyu Explaining Fishes fish, amphibians, crustaceans, reptiles, etc ...
Intensifier
... More specifically, they derive from a group of words called adverbs of degree, also known as degree adverbs ... However, when used grammatically as intensifiers, these words cease to be degree adverbs, because they no longer quantify the idea they modify ... words moderately, slightly, and barely are degree adverbs, but not intensifiers ...
Bulgarski - Grammar - Adverbs
... The most productive way to form adverbs is to derive them from the neuter singular form of the corresponding adjective (бързо (fast), силно (hard), странно (strange ... The same pattern is used to form adverbs from the (adjective-like) ordinal numerals, e.g ... The remaining adverbs are formed in ways that are no longer productive in the language ...
Cebuano Grammar - Adverbs - Deictics
... The 'ng-' forms are always tenseless ... They follow the words or phrases they modify and can substitute equivalent past forms ...