Standing during Aseres Hadibros:
It is an old custom amongst many communities to stand during the reading of Aseres Hadibros. Some Poskim, however, rule one is not allowed to stand during Aseres Hadibros. Practically, the Chabad custom is to stand, facing the Sefer Torah. If the entire congregation is standing then one is obligated to stand together with them, even if in general he is accustomed to sit.
The punctuation for the reading of the Aseres Hadibros: In the Ten Commandments, there are two forms of reading melodies. The readings differ in their stop points within the verses and in their vocalization.
First method: In the first method each command is read as a single verse. This applies whether the command is long [i.e. split to many verses] or short [the verse includes many commands]. This means that the verses of Anochi, Lo Yihyeh Lecha, Lo Saseh Lecha, lo Sishtachaveh and Oseh Chesed is all read as one verse. Likewise, the verses of Zachor, Sheshes Yamim, Yom Hashevi’i, and Vehi Sheses are all read as one verse. Likewise, the two words of Lo Tirtzach is one complete verse. Likewise, the two words of Lo Tinaf is one complete verse. The same applies for the words Lo Tignov. [In this method, the words Tirtzach, Tinaf and Tignov are recited with a Taf and not a Saf.]
Second method: In the second method, each verse is read as a single verse [even if they only contain part of the command or contain more than one command]. Thus, the verse of Anochi is one verse, and the verse of Lo Yihyeh Lecha is a second verse. Likewise, Zachor is read as one verse, and Sheshes Yamim as a second verse. Likewise, the words Lo Tirtzach, Lo Tinaf, Lo Tignov, and Lo Seaneh is all read as one verse.
Final practice: On Shavuos, the custom is to read for the congregation like the first method, to read each command as a separate verse. Furthermore, there are those who are accustomed to read like the first method for the congregation even on Shabbos Parshas Yisro and on Shabbos Parshas Vaeschanan, and only a private individual who reads the verses to himself reads it in the second method.
 See Kaf Hachaim 146:23; Piskeiy Teshuvos 146:6; Beit Maran [Rav Yitzchak Yosef]; Bayit Neman [Rav Meir Mazuz] No. 14; 51; 65; 100; 113
 Ledavid Emes 7:5; Tov Ayin 11; Shaar Efraim 7:37; Kaf Hachaim 146:23; Ketzos Hashulchan 84 footnote 22 that so is custom of world; Igros Moshe 4:22; Shemesh Umagen 57; Mishneh Halachos 11:118
 Teshuvas Rambam 46; Maharikash in Ohalei Yaakov 33; Machazik Bracha 146:8 based on Arizal, brought in Kaf Hachaim 146:23; Opinion in Ledavid Emes 7:5 [He originally writes that it is improper for the entire congregation to stand, and then brings from his Sefer Machazik Bracha that even individuals should not stand, and then concludes that in some communities everyone stands, and ends up defending the practice]; Yechaveh Daas 6:8 rules not to stand and that the custom to stand is to be abolished; Toldos Hair Kavna p. 229 that so ruled the Raavad, Rav Leib Shapiro, to abolish the custom; See Beir Moshe 8:60
 The reason: As it is forbidden to single out a section of Torah, such as the Aseres Hadibros, due to it leading people to believe that only it is the true part of the Torah. [Poskim ibid; See Admur Basra 1:9, Kama 1:10; Rama 1:5; Brachos 12a; Rashba 1:184] However, others negate this worry by stating that the worry is no longer applicable today and does not apply here as one anyways stands for more than just the ten commandments. [See Ulidavid Emes ibid; Shaareiy Rachamim on Shaar Efraim ibid based on Levush 494 and Machatzis Hashekel 429]
 Hayom Yom 24th Shevat; 1st day Chag Hashavuos; 13th Menachem Av; Sefer Haminhagim [English] p. 61; See Shulchan Menachem 1:262 footnote 11 and Chikrei Haminhagim 1:62
 Tov Ayin 11; Shaareiy Efraim ibid; Kaf Hachaim 146:23; Ketzos Hashulchan 84 footnote 22; See Kneses Hagedola E.H. 62; Ikarei Hadaat, and other Poskim brought in Kaf Hachaim ibid; Yechaveh Daas ibid concludes that in such a case he is to stand already from the beginning of the reading; Piskeiy Teshuvos ibid [see there that the same applies vice versa, that if the entire congregation is accustomed to sit then one is not to stand, however, see Ledavid Emes and Kaf Hachaim ibid who write that individuals may stand and see Q&A below!];
 Admur 494:8-11; See M”A 494; Masas Binyamin 6; Elya Raba 142:1; Chizkuni Shemos 20:14
Reading the Aseres Hadibros aloud with the Baal Korei: Some communities were accustomed to read the Aseres Hadibros aloud with the Baal Korei and simply have the Baal Korei recite the last verse aloud, alone. [See Terumas Hadeshen 24; Minchas Yitzchak 3:12] Practically, we do not rule like this custom. [Biur Halacha 146:2 “Velikros”]
 Admur 494:8
 The reason: The reason for this custom is because they follow the way the commands were written in the Torah [I.e. Kesiv], in which each command was written as its own Parsha. From Anochi until Lo Sisa is one Parsha Setuma, and one command, and it is therefore read as a single verse. Likewise, from Zachor until Lo Tirtzach is a single Parsha Setuma. However, Lo Tirtzach until Lo Tachmod is written in four Parshiyos Setumos, as they are four commands, and therefore they are read as four verses. [494:10]
 The reason: As Anochi and Lo Yihyeh Lecha were said simultaneously. It is for this reason that the Nun of the word Panaiy is vocalized with a Patach and not a Kamatz, as there is no stop [Asnachta or end of verse] by it. [Admur ibid]
 The vocalization: It is for this reason that the Chaf of the word “Chol” which is in proximity to the word “Veasisa” is Refuyah and not Degusha. [Admur ibid]
 The vocalization: It is for this reason that the Tzaddik of the word Tirtzach is vocalized with a Kamatz, being that there is a conclusion of verse at this area. Likewise, the Taf is Degusha being that the word Lo is vocalized with a Mafsik, which is a Tafcha. [Admur ibid]
 The vocalization: It is for this reason that the Taf of Tinaf is Degusha and the Alef is vocalized with a Kamatz being that there is a conclusion of verse at this area. [Admur ibid]
 The vocalization: It is for this reason that the Taf of Tignov is Degusha. [Admur ibid]
 Admur 494:9
 One reads the verses as they have been allocated to be read from the Torah [i.e. Keri]. Thus, at times a single verse includes many commands, and at times the same command is read in many verses.
 The vocalization: According to this method, the Nun of Panaiy is vocalized with a Kamatz, being that it represents the end the verse. [Admur ibid]
 The vocalization: According to this method the Chaf of the word “Kol” is Degusha. [Admur ibid]
 The reason: The reason for this custom is because they follow the way the verses are to be read according to Kri, as from Lo Sirtzach until Lo Sachmod there is only one verse. The reason for why this custom does not allow one to stop in middle of the verse and read it in accordance to the commands is because it is forbidden to completely stop in middle of a verse, even when one is reading the verse in private, as all the stop marks in the Torah are a tradition to Moshe from Sinai, and it is forbidden to stop in an area that Moshe did not make a stop in accordance to his tradition from Sinai. Now, since it is forbidden to make a complete stop in middle of these four small Parshiyos [from Lo Sirtzach to Lo Sinaf], therefore, when they are read in one setting they are read in a continuous melody which connects them into one verse, being that they are in truth one verse, as there is no verse in the entire Torah that contains less than three words. Likewise, from Anochi until Lo Sisa and from Zachor until Lo Sirtzach, there are various verses in the reading. Accordingly, a private individual may make a complete stop in the middle of the Parsha of Anochi and Zachor, so long as he does so at the end of a verse. Furthermore, even when reading in public there is no prohibition to stop in these areas due to stopping in middle of a verse, but rather due to those who enter and exit during the reading, as explained in 138:1. Therefore, they are read in a melody that makes a break between them, in order to turn them into many verses, being that in truth they are considered many verses regarding the number of verses they contain. [Admur 494:11; M”A 494; Masas Binyamin 6; Chizkuni Shemos 20:14]
The vocalization: It is for this reason that the Taf of Sirtzach, Sinaf, Signov, Seaneh is Refuyah and the Tzaddik of the word Sirtzach is vocalized with Patach, and the Alef of Sinaf is vocalized with a Kamatz, being that it has an Asnachta. [Admur ibid]
 Admur 494:11; M”A 494; Masas Binyamin 6; Elya Raba 142:1; Chizkuni Shemos 20:14
 The reason: As on Shavuos the Ten Commandments were given and therefore it is read in accordance to the way they were given, which is each command as a different verse. [Admur ibid]