My personal thought is that everyone should be treated equally.

He values his private life.

He was born as an illegitimate child and experienced many difficulties.

My grandfather used to till his privately-owned rice field.

He holds a personal grudge against me.

Using the private railway makes commuting very convenient.

What is the initial velocity of this object?

His first birthday was a very special day.

He stuck to his first thought or decision.

He is learning the basics of Japanese.