Why do some Spanish clubs have a crown on their badges while some don't?

The word "Real" in the club's name is the Spanish term for "royal", and was given by the King Alfonso XIII in 1920 together with the royal crown in the emblem – several other Spanish football teams also received this royal distinction: Real Sociedad, Real Unión de Irún, Real Betis, and Real Zaragoz as well as Real Madrid .sporting Gijon had mural crown till 1936 that is why it has no Real in the club's name.