Many scholarly academics have asked the same question, so we have quite a body of research that tells us when a child is more or less likely to 'grow out of it'.
The variation in children's communication skills in the toddler and preschool stage is huge, and most children fall within the range of normal development. Speech errors are common in little children, but they should have resolved by the time they've completed their first year at school. Children who struggle with both speech and language development in the early years, especially those who struggle to understand what is said to them, are more likely to continue to fall behind their peers. These children benefit a great deal from early diagnosis and therapy. Likewise, children with relatives who had difficulty with language and learning are more likely to have persistent difficulties.
Once children hit school age, the normal range of speech and language ability within their agegroup becomes less varied. Children who were delayed in understanding longer words and sentences at preschool, or those with delays in both speech and language development, are more likely to struggle with learning to read, spell and write fluently. Some children with a family history of difficulties with reading, spelling and learning may only begin to fall behind their peers at this stage. These children may have kept up with their peers in the toddler and preschool years, but begin to struggle when reading and writing become the focus of learning at school. At this stage a child can suffer quite a hit in their self esteem without positive support from family, teachers and a therapist qualified to diagnose and treat their difficulties.
In short, the answer to "Will my child grow out of it?" won't be the same for every child. Early intervention is always best, before difficulties and expectations multiply or self esteem is affected. If you have concerns about your child's speech, language or literacy, just pick up the phone to a Certified Practising Speech Pathologist .