Translation:Shulchan Aruch/Orach Chaim/70
Women and slaves are exempt from reciting the Shema because it is a positive obligation which is time-dependent. But it is correct to teach them to (recite it in order to) accept upon themselves the yoke of the kingdom of heaven. Rema: and they should recite at least the first verse.
Children are exempt, according to Rabbeinu Tam, only before they have reached school age. According to Rashi, even children of school age are exempt because they are not up and about at night-time and they are asleep in the morning. It is appropriate to follow the custom according to Rabbeinu Tam.
One who has married a virgin is exempt from reciting the Shema for three days, if he has not yet consummated the marriage, because he is engaged in the performance of a mitzvah. The preceding words applied at the time of the Rishonim. But nowadays, when everyone's concentration is not as it should be, someone who has recently married a virgin is required to recite it. Rema: see below Chapter 99 on the question whether a drunkard is required to recite the Shema.
If one is engaged in work for the needs of the community and the time for reciting the Shema arrives, he should not interrupt his work. Rather, he should finish his tasks and then recite the Shema if there remains time left for him to do so.
One who is engaged in eating, or washing, or cutting his hair or scraping oil from his skin or one who is involved in a court-case:
(a) according to the Rambam, he should complete what he is doing and afterwards recite the Shema. If he fears that the time for reciting the Shema may pass and he interrupts his activity and recites it, then he is praiseworthy.
(b) according to the Ra'avad, he should interrupt his activity and recite the Shema, even if there will be time left over to recite it afterwards.