Learn Russian: Мы получили сообщение от нового отправителя. - We received a message from the new sender.

In Russian, от is used when something or someone comes from a person (like a sender, friend, or doctor). The preposition из is used when moving out of a physical place or container (like a city or a room). Since the message came from a person, we use от.

Why do the words for 'new sender' change to нового отправителя?

The preposition от always forces the following noun phrase into the Genitive case. For the masculine noun отправитель (sender), the soft sign -ь changes to -я. The masculine adjective новый (new) changes to its Genitive form, нового. Remember that the -ого ending is pronounced like '-ovo'.

Since отправитель ends in a soft sign (-ь), how do we know it is masculine so we can use the right endings?

Nouns ending in -тель are masculine. This suffix is usually added to a verb to describe a person who does that action. Here, the verb отправить (to send) becomes отправитель (sender). Other common examples are учитель (teacher) and писатель (writer).

Why use the perfective verb получили here instead of получали?