Learn Russian: Эта женщина так громко рыдала, что все проснулись. - This woman sobbed so loudly that everyone woke up.

In Russian, you use так (so) before adverbs like громко (loudly) and before verbs. You use такой (such) before nouns and adjectives. Because she was sobbing so loudly (an adverb), так is the correct choice to build the так ... что (so ... that) result structure.

Why are there two different verb aspects in this sentence: рыдала and проснулись?

рыдала is imperfective because it describes an ongoing, continuous background action (she was sobbing). проснулись is perfective because it describes a single, completed event (everyone woke up) that happened as a result of that ongoing sobbing.

I usually use плакать for crying. What is the difference between плакать and рыдала?

плакать is the general everyday word for to cry. рыдать (the infinitive of рыдала) is much stronger and more dramatic. It specifically means to sob, to weep heavily, or to wail.

Why does the word for everyone, все, look so similar to всё (everything)?

They are different forms of the same root word for all. все (ending in e) is the plural form, used for people, meaning everyone or all of them. всё (with the letter ё) is the neuter singular form, meaning everything. In this sentence, people are waking up, so we use the plural все.