Word Finding Difficulty (WFD) otherwise known as Dysnomia or Anomic Aphasia is difficulty recalling words correctly. In children it is more commonly part of a developmental difference rather than as a result of injury to the brain. WFD is most commonly identified as part of language based learning disabilities such as Specific Language Impairment and Dyslexia.
A person with WFD often has difficulty recalling the exact word they want to use in conversation. They may get around this by using less specific words like 'thing' or 'stuff', using umms, aahs and pauses or describing what they mean in a round about way. Sometimes the person is aware they can't think of the right word, and sometimes they just use the wrong word or mispronounce the word without realising, even when the correct word is part of their normal vocabulary.
In normal development, children build their vocabulary through lived experiences and what they hear and read. Not knowing the correct word for something is normal if we have not come across that word many times in life. For children with WFD, the difficulty can occur even with common everyday words, such as not remembering the name of their teacher, or saying 'mango' or 'lemon' instead of 'melon' by accident.
If your child seems to have difficulty using the correct words when talking about everyday things, or makes obvious errors on words they know, they would benefit from assessment by a Speech Pathologist.