When speech is delayed, why is it necessary to check hearing?

Children with Down syndrome often have hearing issues, including mild or fluctuating hearing loss. It's not only a matter of not hearing sound at all — there can be differences in what they catch depending on volume and pitch, difficulty picking up consonants or word endings, and trouble understanding in noisy places. It's not a fixed way of hearing where "strong sounds get through and only faint ones are missed" — it differs by child and by period. Since you can't judge from visible reactions alone, have regular hearing evaluations, and if there's any change in their responses or language growth, consult an ENT doctor or a hearing specialist.