The following Nisargadatta Maharaj audio was recorded in 1979.
“[Nisargadatta] Maharaj used to conduct morning and afternoon talks, mostly in a question-answer form, with the translator sitting next to him. A small group would also join him in meditation at 6:30 in the morning. Additionally, there was a small gathering later in the evening with the conversation being conducted in Marathi.” (Source: Suresh N. Mehta)
You can find more Nisargadatta Maharaj audio here