Similarities:
* Basic grammar: The core grammatical structure of Brazilian Portuguese is very similar to European Portuguese, with shared verb conjugations, noun genders, and sentence structure.
* Vocabulary: While there are some differences in vocabulary, the core words are mostly the same. You'll find a lot of overlap in everyday language, with a few regional variations.
Differences:
* Pronunciation: This is the most noticeable difference. Brazilians have a distinct pronunciation, using nasal vowels and rolling 'R' sounds more consistently than Europeans.
* Vocabulary: Some words are unique to Brazil, and some words have different meanings in Brazil compared to Europe. For example, "azeitona" (olive) in European Portuguese can be "oliva" in Brazil.
* Informal language: Brazilian Portuguese tends to be more informal and colloquial than European Portuguese. Slang words and expressions are used more frequently.
* Regional variations: Just like any language, there are regional differences within Brazil itself. The Portuguese spoken in Rio de Janeiro will differ slightly from the Portuguese spoken in São Paulo.
How different is it?
It's not as different as, say, Spanish and Portuguese. A speaker of European Portuguese can generally understand Brazilian Portuguese with a little effort. However, it's a significant enough difference that a Brazilian might not always understand a European Portuguese speaker without some practice.
In conclusion:
While Brazilian Portuguese has its own distinctive characteristics, it's still a dialect of Portuguese. The core grammatical structure and much of the vocabulary is shared with other varieties. With a bit of effort, speakers of different varieties of Portuguese can communicate effectively.