Right. So basically this is nothing at all to do with Pascal, but is down to (a) the typefaces available in your chosen OS (whether it be a desktop environment or some sort of terminal) and possibly (b) the typesetting used wherever you got the original code (you haven't told us whether it was an academic paper, a printout, or something machine-readable).
Nothing To Do With Pascal. In the same way that people who criticise C because the braces can be confused with parentheses should be yelling at their hardware suppliers, not criticising the language.
OK, having got that out of the way I will relent somewhat, and concede that when ALGOL was designed they specifically selected a character repertoire that made it suitable for published papers: they didn't necessarily intend that that would also be used for coding. But in any event, they chose nice unambiguous BEGIN and END rather than any special characters available to the ACM and AMS typesetters.
But at the same time, virtually all ALGOL derivatives have fouled things up by allowing "I", 'l" and "1" in identifiers. But they couldn't very well exclude capital i because of its special significance to FORTRAN. And then there's "O" and "0", ' vs ` and so on.
And all of the original ALGOL derivatives allowed block-local variables to "shadow" those further away, and didn't even attempt to raise a warning if they realised that the name of a variable was a substring of another. Now mix /that/ in with Pascal's case-insensitivity, which was the result of Wirth coming from a 6-bit character CS background rather than a 7-bit character comms one.
It's a mess, and gets worse when one considers Unicode and the (in effect) multiple codepages it tries to support.
But the original OP problem is nothing to do with Pascal, or with any other language: it's a hardware and OS issue.
Here endeth the rant. Pax vobiscum.
MarkMLl