And they differed regarding the one who is forgetful, unaware, coerced, asleep, the person who warns a blind man, or the one who speaks for the benefit of the prayer:

• The Ḥanafīs and Ḥanbalīs hold that the prayer is invalid in every one of these situations, basing themselves on the ḥadith under discussion and on the report in which the Companions said to the Prophet, peace and blessings be upon him, “We used to greet you with salām during the prayer and you would return our greeting.” He replied, “In the prayer one is already fully occupied.” This ḥadith is agreed upon, along with other proofs.

• Imāms Mālik and al-Shāfiʿī, on the other hand, rule that the prayer of a person who speaks out of ignorance, forgetfulness, or because he thinks he has finished—so he gives the salām and then speaks—remains valid, whether the speech concerns the prayer or not, and whether he is an imam or a follower. In their view the latter part of the prayer is simply joined to the former, leaving it complete. This opinion is also one narration from Imām Aḥmad, and was preferred by Shaykh al-Islām and many later scholars. Their evidences include:
a) The ḥadith of Dhu’l-Yadayn, which will be discussed under the prostration of forgetfulness (sujūd al-sahw).
b) The ḥadith, “My ummah has been excused for what they do by mistake, out of forgetfulness, or under compulsion.”
Accordingly, the ḥadith presently under review is understood to apply to someone who speaks knowingly and deliberately.

They also disagreed about blowing, clearing the throat, groaning, moaning, sobbing, and similar sounds:

• The Ḥanafīs, Shāfiʿīs, and Ḥanbalīs rule that these invalidate the prayer if they combine to form two articulated letters. If they do not reach that extent, or if the sobbing is from fear of Allah, or the throat-clearing is done out of necessity, the prayer is not invalidated.

• Shaykh Taqī al-Dīn (Ibn Taymiyyah) held that such sounds do not invalidate the prayer even if two letters are formed, arguing that they are not of the same category as speech and therefore cannot be analogically equated with it.

Summary:
Words fall into three categories:
1 – Words that carry meaning by themselves, such as “hand,” “mouth,” “tooth,” and the like.