In the provided sentences, four can be structured into a coherent paragraph, while one sentence doesn't fit logically. Let's examine the context:
- People who study children's language spend a lot of time watching how babies react to the speech they hear around them.
- They make films of adults and babies interacting, and examine them very carefully to see whether the babies show any signs of understanding what the adults say.
- They believe that babies begin to react to language from the very moment they are born.
- Sometimes the signs are very subtle - slight movements of the baby's eyes or the head or the hands.
- You'd never notice them if you were just sitting with the child, but by watching a recording over and over, you can spot them.
Sentences 1, 2, 4, and 5 collectively discuss the process of observing and analyzing babies’ reactions to speech, frequently using recordings to notice subtle cues. Sentence 3, "They believe that babies begin to react to language from the very moment they are born," introduces a belief and is an outlier to the detailed observational process described by the other sentences.
Therefore, the odd one out is:
Sentence 3: They believe that babies begin to react to language from the very moment they are born.