ja

In a sentence

• Ja rīt būs silts, mēs iesim uz pludmali.

  If it is warm tomorrow, we will go to the beach.

  In this sentence, 'ja' is used as a subordinating conjunction meaning 'if', used to introduce a conditional clause.

• Es viņam jautāju, ja viņš vēlas pievienoties vakariņām.

  I asked him if he would like to join for dinner.

  Here, 'ja' is used as a direct translation of 'if', introducing a reported yes/no question.

• Ja nu viņi tomēr neatnāk, mēs iesim vieni.

  If they still don't come, we will go on our own.

  In this example, 'ja' is used again as 'if', combined with 'nu' to add a hypothesis or doubt aspect.