Yes, upper register. Its index in Serbian and that's what we used in Introductory Linguistics when I was still going to college.

The languages I know or can understand are mainly Slavic. For example if I go to any Slavic language Wikipedia I can read any article. In school I have studied (apart from Slovak and Serbo-Croatian which are native to me) only Russian. The rest I have just practised by reading and listening. Studying Old Church Slavonic and reading Comparative linguistics of Slavic languages helped me understand how Slavic languages separated and in what way they are different and same. So even if I come to a word I have never seen before I can compare it to a word from one of the Slavic languages I do know and discover its meaning. Same goes for morphology. Of course there are exceptions when a word is unique for a language in which case I consult a dictionary, but I do that rarely.

One thing I do though when reading another Slavic language is that I pronounce the words the way they would be in my own language. For instance, I always pronounce Polish /rz/ or Chech /ř/ as [r], the way it is in Slovak, or Polish /y/ and Russian /ы/ as [i], not [ɨ], or Polish /ą/ as [u]. I also pronounce accents and vowels longer or shorter according to where they are pronounced in Slovak. This doesn't help me in learning the language, but it makes it reading hell of a lot easier.

why don't you pronounce it like you would ž (or š depending on the situation)?

Because Czech /ř/ and Polish /rz/ is cognate with /r/ in all other Slavic languages. It is easier for me to understand the words then.

How do you pronounce Bulgarian <ъ>?

As a very short undefined back vowel.

So what are your thoughts on Polyglottery? I find it inspiring to learn more languages, despite most of them being dead languages.

Given the difficulty of some of the languages I've chosen, there's probably a limit to the number I can reasonably expect to acquire. But I plan to speak at least a handful fluently.

Like the guy you have posted about, polyglottery doesn't necessary imply being fluent in all those languages, but having a commendable knowledge of them. (Fluency is something so freaking hard to obtain anyway.)

Fluency is a sliding scale. I might be able to skim Spanish Wikipedia with no problems and hold basis conversations with other learners, but when it comes to scientific or technical discourse I'm lost.

I have passive knowledge in MANY languages. I can read newspaper articles in upwards of 20 languages, albeit slowly. But when it comes to making my own sentences in a grammatically correct way, that's where I lack the skills to pay the bills
(Unfortunately I know only about 500 Chinese characters which makes me practically illiterate in Chinese )