The Leningrad Codex (LC) shows two parallel systems of cantillation for the Decalogues, which later came to be known as "Lower" cantillation and "Upper" cantillation. (The word for cantillation in Yiddish is "trope".) Cantillation marking consists of vowels (including dagesh, rafe), punctuation, as well as the cantillation marks themselves. The origin of the Lower cantillation is thought to be Tiberian, the origin of the Upper, Babylonian. The Lower cantillation is for ordinary reading; the Upper cantillation is for special occasions according to the local practice.

The difference between Lower and Upper cantillation lies in the way the verses are divided: Lower cantillation divides the Decalogue into verses of typical length, which means that some of the longer "commandments" contain more than one verse, while the shortest "commandments" are combined into a single verse. The “Upper” cantillation divides the 10 "commandments" into 10 verses, i.e. each "commandment" is exactly one verse. This leads to some extremely long verses and some very short verses. Since cantillation is entirely dependent upon the division of the text into individual verses, the two different ways of dividing the verses results in the two different systems of cantillation.

Many printed editions of the Hebrew Bible divide the two different systems of cantillation and show them separately. Others show only the Lower cantillation in the primary text and provide the Upper cantillation in an appendix. The LC, like other Tiberian manuscripts, does neither of these things. Rather it combines the two different systems placing the marks for both the Lower and Upper cantillations for relevant words in the text, often marking the very same consonant in two different ways. If a consonant has marks of the same type (vowels, cantillation), at the same level i.e. above or below the consonant, the first (in the right-to-left direction) is Lower cantillation, the second is Upper cantillation.

Because the order of the accents is important, the underlying UXLC text ignores mark ordering conventions to place the marks in the same order as the LC. To see the actual order of the marks in the UXLC text, see "Viewing details of selected Hebrew text". This is helpful when the rendering of displayed text is jumbled.

Not all texts with Upper markings follow the LC, even if the primary text is from the LC. They may follow a later tradition called the "Printed Editions" tradition in the Hebrew Wikisource page below.

Double cantillation is found in one other place in the LC, Genesis 35:22, The Saga of Reuven, which is read either as a single verse or divided into two verses. A Hebrew Wikisource page below provides a comparison of these divisions.

Suggested further study:

The excellent Hebrew Wikisource page Decalogue by Seth (Avi) Kadish provides a impressive variety of comparisons of Decalogues with Lower and Upper cantillations for both the Tiberian tradition and the Printed Editions tradition. Comparisons of Exodus and Deuteronomy Decalogues with different cantillations and from different traditions are also included.

The Saga of Reuven, Gen 35:22, is shown with two divisions at https://he.wikisource.org/wiki/בראשית_לה/טעמים#מעשה_ראובן by the same author.

The Unicode text for these pages is from a critical edition based upon Tiberian manuscripts (most importantly the LC) following the analysis of Mordechai Breuer, The Aleppo Codex and the Accepted Text of the Bible (Jerusalem: Mosad Harav Kook, 1976), pp. 56-67 (Hebrew). The UXLC represents only one Tiberian manuscript, the LC. Text differences between the site's text and the UXLC text can be expected due to editing conventions and minor idiosyncrasies in the LC.