Complex sentence: It is believed that Patti learned much of her singing technique from her brother in law Maurice Strakosch, although later in life Patti, like many famous singers, claimed that she was entirely self-taught.
Split into simpler sentences: It is believed that Patti learned much of her singing technique from her brother-in-law Maurice Strakosch. Later in life Patti, like many famous singers, claimed that she was entirely self-taught.