Significant speech and language delays are directly related to developmental or health issues. However, some people blame speech and language delays on factors that are not the cause of true delays, such as:

• Developmental variation. Mild and temporary speech delays can occur. And some children learn new words faster than others do. But if your child is not saying words by 18 months, or can say fewer than 50 words by 24 months, talk to your doctor. Don't assume that delays are the result of normal developmental differences.
• Laziness. Young children instinctively practice speech and language as these skills emerge. While they do not hold back out of laziness, they may do so because of intimidation, stress, fear, or other problems.
• Having older siblings. Younger children may begin to talk slightly later than their older brothers or sisters did. However, having one or more older siblings does not cause significant speech and language delays.
• Being a boy. Girls usually are ahead of boys in language development after the first year, but there is only a slight difference. Significant delays are not caused by gender.
• Bilingualism. Children raised in bilingual homes may have a slight delay in beginning to speak. They also may mix both languages until they are about 3 to 4 years old, after which they usually speak them both well. Children who grow up in bilingual homes do not have more difficulty in learning to talk, read, and write than those who are learning one language. In fact, learning two or more languages at a young age may boost a child's overall ability to learn.