Understanding Reading Order |
There are two senses in which text can have a reading order. Each language has an inherent reading order and, in text that mixes languages, there is a reading order for the separate runs of characters from each language.
The inherent reading order of a language is the direction in which its symbols are read and written. Most languages read from left to right, as does English, Spanish, and Russian. A few, such as Hebrew and Arabic, read from right to left. Examples:
English is Left-to-Right (LTR):
People ought to wear more hats.
Start→
Hebrew is Right-to-Left (RTL):
אנשים צריכים ללבוש יותר כובעים.
←Start
When a line includes text from both RTL and LTR languages, then it consists of separate runs of characters from each language. Within a run, the characters use the language's inherent reading order. But the series of runs also has a reading order, defined by the author's intent. When some Hebrew is included in text intended for English readers, then the overall reading order is LTR. In this example, the numbers indicate the reading order of the runs and the arrows show the reading order within each run:
The Hebrew word for hat is כובע, which is hard to pronounce.
|1 → |←2 | 3→ |
When English is included in Hebrew, the overall reading order is RTL:
המילה של אנגלית לכובע hat, שקשה לבטא.
| ←3|2→| ←1|
When text is printed with the wrong reading order, the results can be dramatic. The following text, which is a translation into Hebrew of the English term 2.5" Screw, is displayed LTR as intended.
2.5" הברג
|1→| ←2|
If the text were displayed RTL, it would look like this:
2.5" הברג
| ←2|1→|
For this reason,