In German, the conjugated verb always stands in the second place in a main clause (e.g. in a simple sentence).
Most often, what comes before it (in the "Vorfeld" position) is the subject, but there are other words that can be at the beginning of the sentence, such as an adverb like "normalerweise" or an object. In that case, the verb stays in the second position, and the subject has to come later in the sentence, usually right after the verb.
English only has traces of this, in sentences such as "Thus shall it be done" (with "it" coming after the verb because "Thus" is in first position) or "So be it".
Admittedly it would usually be asked "Is it normally green" but in cases of stressing the normality, i've questioned and heard others question things that way. "Those red bottles are nice but normally do they use red bottles?" "Traffic's really slow on this road today but normally is it this slow?" Of course it might be colloquial phrasing as well.
I can hear myself saying 'Normally is it green?'. I'm a native (American) English speaker but I'll suggest two answers to your question. I think 'ist es normalerweise grun' could be translated to 'Normally is it green?'. Another possibility is 'Ist normalerweise es grun' but I don't know how it would sound to a native.
Yes, the two are related.
They're both from a noun Weise / "wise" meaning something like "way, manner", from a construction along the lines of "in a ... way" (e.g. likewise from something like "in like wise" ="in a similar manner"; normalerweise from something like in normaler Weise "in a normal way").
Also related is English guise which came into French from a Germanic language and has the same origin as wise and Weise.
In general, the bare adjective (without an ending) is used as the adverb.
Das Auto ist schnell (adjective, the car is fast) / Das Auto fährt schnell (adverb, the car drives quickly)
Der Junge ist gut (adjective, the boy is good) / Der Junge singt gut (adverb, the boy sings well)
Some use -erweise as in "normalerweise" (normally), "seltsamerweise" (strangely; oddly enough) - I'm not sure of a rule but perhaps this is more common in sentence adverbs that describe not a verb but the whole sentence (in English, these would usually be set off with commas at the beginning of a sentence). Literally something like "in a .... way".
Compare, for instance:
- Er läuft normal. = He runs normally. = He runs in a normal way. (regular adverb)
- Er läuft normalerweise. = Normally, he runs. = In general / usually, he runs. (sentence adverb.)
Yes, the sentence is affirmative, that is why the verb ist is in the second position of the sentence, not in the first where it would be if it were a question or a command.
But because there's an adverb before the verb here, there's no room for the subject as well (otherwise there would be two things before the verb and the verb would be the third thing in the sentence, not the second) -- and so the subject has to come after the verb.