1. Indo-European languages: This is the largest language family in the world, encompassing languages from Europe, Asia, and parts of the Americas. It is believed that the Proto-Indo-European language, the ancestor of all Indo-European languages, originated somewhere in the Pontic-Caspian steppe around 4500-2500 BCE.
2. Indo-Aryan languages: This branch of the Indo-European language family is spoken primarily in the Indian subcontinent. It includes languages like Hindi, Urdu, Bengali, Marathi, Punjabi, and many others. The Proto-Indo-Aryan language, the ancestor of these languages, is believed to have originated in the northwest of the Indian subcontinent around 2000 BCE.
3. Indo-Iranian languages: This is a sub-branch of the Indo-European language family that includes both the Indo-Aryan languages and the Iranian languages (e.g., Persian, Pashto, Kurdish).
4. "Indo" as part of a compound term: This is often used to indicate a connection to India, such as in terms like "Indo-Tibetan", "Indo-Pacific", or "Indo-Chinese".
So, to answer your question more specifically, you need to clarify what you mean by "Indo-language".
If you're asking about the origin of the Indo-Aryan languages, then they come from the Proto-Indo-Aryan language, which itself is descended from the Proto-Indo-European language.
If you're asking about the origin of the Indo-European languages in general, then they come from the Proto-Indo-European language, which is believed to have originated in the Pontic-Caspian steppe.
Please provide more context or information about the specific "Indo-language" you're interested in, and I can give you a more precise answer.