Learn Finnish: Me annamme vettä norsuille kello kaksitoista. - We give water to the elephants at twelve o'clock.

To make the allative plural, we add the plural marker i and the allative ending -lle to the stem of the word. Since norsu ends in -u, the i simply attaches to it, making the final word norsuille.

Why do we use the allative case for the elephants here?

In Finnish, the recipient of an action like giving, telling, or sending takes the allative case (the -lle ending). It serves the exact same purpose as saying 'to the elephants' in English.

Why is the word for water, vettä, in the partitive case?

Water is an uncountable mass noun. Because the elephants are receiving an unspecified amount of water (some water, not all the water in the world), it must be in the partitive case. The basic dictionary form is vesi.

Why doesn't kello kaksitoista have a location ending to mean 'at' twelve o'clock?

When stating an exact hour, Finnish simply uses the basic nominative forms of kello and the number. You do not need an extra word or case ending to express 'at' when telling the time like this.