At the age of 3-4 years, your child is developing his verbal skills. He is not able to talk properly. He skips or deletes a syllable in a multisyllabic word. He tries to simplify words with blends. He is still mastering all the sounds in his language. He may still pronounce 'goggie' for 'doggie'.
What you need to know:
You should keep talking to your child. Make him talk to his peer groups. Point out his mistakes and correct his speech. Play with him and constantly, repeat those words. Gradually, he will grow in age and with practice, as he listens, he will learn to speak new words correctly. Sometimes, speech development is late and other times there is some serious disorder. Even after a year or two if speech remains the same then there is some serious issue. Consult a paediatric - speech language specialist as soon as possible. He will diagnose the correct reasons behind this problematic situation and provide you a way out of the problem.