<<I realise that languages become more complex in certain ways. However, having had the pleasure of learning Norwegian and attempting to learn Icelandic, I can assure you that some languages most certainly do become simpler as time passes.>>
Well, not quite. Even there you're just referring to certain aspects of language which have experienced simplification. Is Icelandic morphology more complex than Norwegian's? Most definitely. But that's just morphology you're looking at.
Also, the written standard of Icelandic which has changed comparatively little in a millennium masks the changes that have occurred in the spoken language over the past thousand years. Let's look at a little example in the realm of phonology. Norwegian (whether we're talking about Bokmål or Nynorsk) has maintained Old Norse rounded high front vowels /y:/ and /Y/ while Icelandic has actually experienced a simplification here, as the Old Norse vowels /y:/ and /Y/ have merged with /i/ and /I/ in Modern Icelandic (this is not to be confused with Modern Icelandic /Y/ which is descended from Old Norse /u/). The distinction is still made in spelling but has not been made in the spoken language for many centuries. Thus the Icelandic word "yrði" has two separate orthographical letters yet both vowels are /I/.
Compare to Norwegian "ny" /ny:/ and "ni" /ni:/. Here Norwegian maintains the two-way distinction lost in Icelandic.
Another phonological example. Norwegian has pitch-accent distinctions which either came from Old Norse (scholars are not sure whether or not Old Norse had pitch-accent distinctions) or developed along the way but Icelandic does not have them. Either Icelandic lost them from Old Norse (thus a simplification) or Norwegian (and some Swedish dialects) developed this complexity independently even as they were simplifying in the area of cases (either way that it happened, this is another area where Norwegian is more complex).
The point is it's definitely true that certain aspects of language can simplify. But language is so much more than just cases alone or sounds alone or syntax a lone. Just looking at one aspect of language is not enough to say anything about it as a whole. When you look at even a few aspects in the developmental history of any language you'll find some get simpler and some get more complex as time marches forward (and often it's hard to even say whether something got simpler or more complex--it just changed).
<<Anyway, despite the fact that I may be completely wrong (which wouldn't surprise me as I make no claim to a wide knowledge of linguistics), you have basically just disproved Euro's point that English grammar is simpler than, say German, and thus the reason that "English speakers are linguistically disabled".>>
Ah, well I haven't had time to thoroughly read Euro's comments but since they're nonsense and your comments seemed sincere I responded to yours.
<<I meant, that the Norse language became simpler to learn, not just simpler.>>
Has it? Maybe in some areas, like morphology. But what about something like the pitch-accent tonal distinctions I mentioned above? If you are not familiar with such phenomena having to learn the distinction is going to be more difficult in learning Norwegian as compared to Icelandic because Icelandic does not have it. Or what if your native language doesn't have /y/ but does have /i/ (almost all languages have the latter)? Mastering Norwegian /y/ will require some effort that mastering Icelandic /i/ won't, because Icelandic doesn't have /y/ anymore.
A language's level of difficulty is not a universal but depends on your native language. If you speak Arabic natively learning Hebrew will be easier for you than learning Estonian. If you speak Estonian natively then learning Finnish will be easier for you than learning Arabic. However, it's not a universal that Arabic is harder than Finnish or vice versa.
<<Out of genuine interest:
Finnish is agglutinative is it not? Do those actually qualify as cases?>>
I'm not an expert on Finnish but I do know it's agglutinative and displays a high degree of synthesis. Anything I've ever read about Finnish has always talked about the many Finnish cases, tho of course they don't work in exactly the same ways cases do in, say, Latin or German.
<<Also, is Russian a direct descendent of Old Church Slavonic? How many cases did OCS have?>>
No, Russian isn't a direct descendant of OCS but it was definitely influenced by it over time. I'm not sure about cases in OCS--someone here who knows more about Slavic languages should comment.
Well, not quite. Even there you're just referring to certain aspects of language which have experienced simplification. Is Icelandic morphology more complex than Norwegian's? Most definitely. But that's just morphology you're looking at.
Also, the written standard of Icelandic which has changed comparatively little in a millennium masks the changes that have occurred in the spoken language over the past thousand years. Let's look at a little example in the realm of phonology. Norwegian (whether we're talking about Bokmål or Nynorsk) has maintained Old Norse rounded high front vowels /y:/ and /Y/ while Icelandic has actually experienced a simplification here, as the Old Norse vowels /y:/ and /Y/ have merged with /i/ and /I/ in Modern Icelandic (this is not to be confused with Modern Icelandic /Y/ which is descended from Old Norse /u/). The distinction is still made in spelling but has not been made in the spoken language for many centuries. Thus the Icelandic word "yrði" has two separate orthographical letters yet both vowels are /I/.
Compare to Norwegian "ny" /ny:/ and "ni" /ni:/. Here Norwegian maintains the two-way distinction lost in Icelandic.
Another phonological example. Norwegian has pitch-accent distinctions which either came from Old Norse (scholars are not sure whether or not Old Norse had pitch-accent distinctions) or developed along the way but Icelandic does not have them. Either Icelandic lost them from Old Norse (thus a simplification) or Norwegian (and some Swedish dialects) developed this complexity independently even as they were simplifying in the area of cases (either way that it happened, this is another area where Norwegian is more complex).
The point is it's definitely true that certain aspects of language can simplify. But language is so much more than just cases alone or sounds alone or syntax a lone. Just looking at one aspect of language is not enough to say anything about it as a whole. When you look at even a few aspects in the developmental history of any language you'll find some get simpler and some get more complex as time marches forward (and often it's hard to even say whether something got simpler or more complex--it just changed).
<<Anyway, despite the fact that I may be completely wrong (which wouldn't surprise me as I make no claim to a wide knowledge of linguistics), you have basically just disproved Euro's point that English grammar is simpler than, say German, and thus the reason that "English speakers are linguistically disabled".>>
Ah, well I haven't had time to thoroughly read Euro's comments but since they're nonsense and your comments seemed sincere I responded to yours.
<<I meant, that the Norse language became simpler to learn, not just simpler.>>
Has it? Maybe in some areas, like morphology. But what about something like the pitch-accent tonal distinctions I mentioned above? If you are not familiar with such phenomena having to learn the distinction is going to be more difficult in learning Norwegian as compared to Icelandic because Icelandic does not have it. Or what if your native language doesn't have /y/ but does have /i/ (almost all languages have the latter)? Mastering Norwegian /y/ will require some effort that mastering Icelandic /i/ won't, because Icelandic doesn't have /y/ anymore.
A language's level of difficulty is not a universal but depends on your native language. If you speak Arabic natively learning Hebrew will be easier for you than learning Estonian. If you speak Estonian natively then learning Finnish will be easier for you than learning Arabic. However, it's not a universal that Arabic is harder than Finnish or vice versa.
<<Out of genuine interest:
Finnish is agglutinative is it not? Do those actually qualify as cases?>>
I'm not an expert on Finnish but I do know it's agglutinative and displays a high degree of synthesis. Anything I've ever read about Finnish has always talked about the many Finnish cases, tho of course they don't work in exactly the same ways cases do in, say, Latin or German.
<<Also, is Russian a direct descendent of Old Church Slavonic? How many cases did OCS have?>>
No, Russian isn't a direct descendant of OCS but it was definitely influenced by it over time. I'm not sure about cases in OCS--someone here who knows more about Slavic languages should comment.