Great care has always been taken in preserving successfully the text of the Torah
In Accuracy of Torah Text Aish HaTorah’s Discovery Seminar writes:
The meticulous process of hand-copying a scroll takes about 2,000 hours (a full-time job for one year). Throughout the centuries, Jewish scribes have adhered to the following guidelines:
Success of the System:
Maintaining the accuracy of any document as ancient and as large as the Torah is very challenging even under the best of circumstances.
But consider that throughout history, Jewish communities were subject to widespread persecutions and exile. Over the last 2,000 years, Jews have been spread to the four corners of the world, from Yemen to Poland, from Australia to Alaska.
Other historical factors make the accurate transmission of the Torah all the more difficult. For example, the destruction of the Temple 1,900 years ago saw the dissolution of the Sanhedrin, the Jewish central authority which traditionally would unify the Jewish people in case of any disagreements.
Let’s investigate the facts as we have them today. If we collect the oldest Torah scrolls and compare them, we can see if any garbling exists, and if so how much.
How many letters are there in the Torah? 304,805 letters (or approximately 79,000 words).
The fact is, that after all the trials and tribulations, communal dislocations and persecutions, only the Yemenite Torah scrolls contain any difference from the rest of world Jewry. A total of nine letter-differences are found in their scrolls.
These are all spelling differences. In no case do they change the meaning of the word. For example, how would you spell the word “color?” In America, it’s spelled C-O-L-O-R. But in England, it’s spelled with a “u,” C-O-L-O-U-R.
Such is the nature of the few spelling differences between Torah scrolls today. The results over thousands of years are remarkable!