Can Shema be said while lying in bed?

A person may recite Kriyas Shema in any position—whether sitting, standing, walking, reclining, or riding on an animal. When reclining, though, one may not say Shema while lying directly on his back or stomach. A slight tilt to the side is also not acceptable. According to Shulchon Aruch, if one is fully on his side, saying Shema is permitted l’chatchilah. Rema maintains that one may only say it while lying down if he is undressed and it would be a bother to get up, get dressed, and say Shema. If a person is dressed when he is reclining, he must get up to say Shema. The Achronim disagree about whether the leniency permitting the recitation of Shema while walking applies only when a person is travelling or whether it can be relied upon even if one wishes to walk around in shul.

סעיף א' ס"ק א-ג ביאורים ומוספים דרשו 1

When is it forbidden to be stringent?

According to the opinion of Bais Shamai, a person must recite the daytime Shema while standing and the nighttime Shema while lying down. They explain the words b’shochbecha (when you lie down) and u’vkumecha (and when you stand up) literally. Bais Hillel maintains that these words are referring to the times to say Shema and holds that the Torah is not particular about the person’s position when saying Shema. The halacha follows Bais Hillel, and the Chachomim enacted a prohibition against being stringent like Bais Shamai. In keeping with this prohibition, it is forbidden to rise from sitting to standing when saying Shema in the morning or to shift from standing to reclining when saying Shema in the evening. If there is another obvious reason to change one’s position, doing so is permitted. For example, one may rise (during the daytime Shema) to respond to Kedusha. The poskim are also lenient in allowing restless people to stand up and sit down during Shema.

סעיף ב וס"ק ה ו־ז; ביאורים ומוספים דרשו, 7-6

Can Shema be said while driving?

Although one may say Shema while walking, he must stop during the first two pesukim. A person can only achieve the proper kavana necessary for these pesukim when he is stationary. Some are stringent and stop through the words of al levovecha. A passenger in a car or wagon does not need to ask the driver to stop when he says the first pesukim. The poskim disagree about whether a person who is driving must stop to say Shema.

סעיף ג וס"ק ט-יא; ביאורים ומוספים דרשו, 11

• It is permissible to daven, recite brochos and say Kriyas Shema in languages other than Lashon Kodesh. One must understand the language, and it must be an accepted language spoken by most of the local populace.

• Kriyas Shema must be read audibly, loud enough for the one reciting it to hear the words. Some say that this is a Torah requirement. The poskim discuss whether one must raise his voice when saying Shema in a noisy room.

• The Gemara discusses whether hirhur is k’dibur--whether thinking a thought is equivalent to articulating it. Most Rishonim rule that it is not, and that a person is not yotzei if he merely thinks the words of Kriyas Shema. 

• Which parts of Shema require kavana?

• Is it permitted to “shush” others during Kriyas Shema?

• Which parts of Shema are Torah obligations?