Learn Hardcore German: Meine Nachbarin ist auch nett und hilft oft im Haushalt. - My female neighbor is also nice and often helps with the household.

It marks a feminine form: die Nachbarin = female neighbor. The male counterpart is der Nachbar (a weak masculine noun: Genitive/Dative/Accusative singular add -n → z. B. des/ dem/ den Nachbarn). Plurals:

feminine-only plural: die Nachbarinnen
mixed/masculine plural: die Nachbarn

Why is it Meine and not Mein?

Because Nachbarin is feminine and in the nominative case (subject). Possessives like mein- take the feminine nominative ending -e: meine Nachbarin. Compare:

masculine nominative: mein Nachbar
plural nominative: meine Nachbarn

What case is Meine Nachbarin?

Nominative; it’s the subject of the sentence.

Why is it nett and not nette?

After a linking verb like sein (to be), adjectives stay uninflected: Sie ist nett. If the adjective comes before the noun, it takes an ending: meine nette Nachbarin.

What does auch mean here, and can I move it?

auch means “also/too.” In this position, it most naturally means “She is also nice” (in addition to something previously mentioned). To say “she also helps,” move auch into the second part:

Meine Nachbarin ist nett und hilft auch oft im Haushalt. If you mean “she also helps (in general),” without focusing on frequency, you can say:
… und hilft auch im Haushalt.

Where does oft go? Are other positions okay?

Default placement for frequency adverbs is before place phrases: hilft oft im Haushalt. Alternatives:

Oft hilft sie im Haushalt. (fronting for emphasis on frequency)
Sie hilft im Haushalt oft. (possible, but it emphasizes the location a bit)

Why hilft and not helfen/helft?

helfen is irregular; 3rd person singular is hilft (e→i). Mini paradigm:

ich helfe
du hilfst
er/sie/es hilft
wir helfen
ihr helft
sie/Sie helfen

Does helfen take the dative?

Yes. If you add a person being helped, it’s in the dative:

Sie hilft mir/ihm/den Kindern im Haushalt.

What is im?

A contraction of in dem (in + the). in takes the dative for location (where?) and the accusative for movement (where to?):

location: im Haus, im Haushalt
movement: ins Haus (in + das)

Why im Haushalt and not bei der Hausarbeit or mit dem Haushalt?

im Haushalt (helfen) is idiomatic and very common. bei der Hausarbeit (helfen) is also very natural and explicit (“help with the housework”). mit dem Haushalt sounds odd for chores; Haushalt can also mean “budget,” so mit may suggest “with the budget.” Note: Haushalt is masculine: der Haushalt.

Do I need a comma before und here?

No. German normally omits the comma between main clauses joined by und. A comma can be used for clarity in long or complex sentences, but it’s not needed here.

Why are there two finite verbs (ist and hilft) in one sentence?

und coordinates two main clauses. The subject is simply omitted in the second one: Meine Nachbarin ist auch nett und (sie) hilft oft im Haushalt. Each clause keeps verb‑second order.

Why are Nachbarin and Haushalt capitalized, and why is Meine capitalized?

All nouns are capitalized in German, so Nachbarin and Haushalt are capitalized. Meine is capitalized only because it starts the sentence; mid‑sentence it would be meine.

How would this change with a male neighbor or with plural neighbors?

Male: Mein Nachbar ist auch nett und hilft oft im Haushalt.
Plural: Meine Nachbarn sind auch nett und helfen oft im Haushalt. Note that Nachbar is a weak noun in oblique cases: e.g., mit meinem Nachbarn.

Any quick pronunciation tips?

Nachbarin: ch like the “Bach” sound ; stress on the first syllable.
auch: “ow” (as in “now”) + that same ch sound.
hilft: clear final -t; consonant cluster -lft.
Haushalt: stress on Haus- (“HAUS-halt”).

Does the present tense here mean “often helps” or “is helping right now”?

German present covers both. Context decides. For “right now,” add gerade: Sie hilft gerade im Haushalt.