Questions & Answers about Я обычно общаюсь с соседкой утром.
Why is it соседкой and not соседка?
The preposition с (meaning "with" for accompaniment) requires the noun to be in the Instrumental case. The feminine noun соседка (female neighbor) changes its -а ending to -ой, becoming соседкой.
Why does the verb общаюсь end with -сь?
This comes from the infinitive общаться (to chat or communicate), which is a reflexive verb (verbs ending in -ся or -сь). For the я (I) form, the normal ending is -ю. Because -ю is a vowel, the reflexive part shortens from -ся to -сь, giving us общаюсь.
Why doesn't утром have a preposition to mean "in the morning"?
In Russian, you don't need a preposition like "in" for parts of the day. Instead, you just put the noun in the Instrumental case. The word утро (morning) becomes утром to mean "in the morning".
How do we know this neighbor is female?
The word itself tells us! The base word is соседка, which specifically means a female neighbor. If it were a male neighbor (сосед), the phrase "with the neighbor" would be с соседом.