It’s been a while since I’ve been back here at the web site. I now see there are 2 separate sets of curriculum. However, whilst trying to understand how they differ, work together I see words like lesson, challenge, course, and level, all thrown about whilst people discuss them and sometimes the words cross-refer between the Courses and Challenges.
Could I please get a firm understanding, maybe a clear taxonomy of what words SSi use and which curriculum it refers to?
Thanks.
Welcome back!
Does the below help?
Lessons make up Courses - these are the earlier SSiW Welsh learning resources
Challenges make up Levels - these are the current SSiW resources
The difference between the two sets is the collection of sentence patterns and words that are used. An example is short verb forms: these are introduced earlier in the Levels than in the Courses. If you were to start from scratch, the recommendation is to start with the Levels.
To add context to Louis’ detailed explanation, the Courses were the “1st generation” of SSiW, while the Levels are the “2nd generation”, or “SSiW 2.0” if you like. 
[quote=“mikeellwood, post:3, topic:6387”]
the Courses were the “1st generation” of SSiW, while the Levels are the “2nd generation”,
[/quote] Or “earlier” and “current”, if you like. 
To reiterate - the ‘courses’ are the outgoing resource, which I believe may still be at least archived once the new ‘levels’ have all been published, and the ‘levels’ will be THE SSiW course to follow if you’re starting out again.
Both North and South dialects have 2 levels published now, with a 3rd level in production as we speak. The new levels have been reworked to get learners speaking Welsh much quicker than before, and without the additional “vocabulary” units - so if you wanted to, say, attend bootcamp, you will only need to complete Level 1 (25 challenges) instead of Course 1 and the vocabulary units (27 lessons (which includes lessons 6.1, 6.2 and bonus lesson 6 - this will be 28 lessons for northern dialect!) and 10 vocab units) - much easier AND you will STILL have enough Welsh to survive bootcamp.
The old ‘courses’ remain for those who still follow this version of the course while the new ‘levels’ are being built, but if you still want to use this version then you can. The recommendation is to try the new ‘levels’ though.
Croeso nôl!
Gav
…unless anyone was planning to bring a giraffe…[if I remember correctly]
I would recommend doing the levels first followed by the courses as they both compliment each other very well. You learn lots of new stuff on the courses (and the vocab lessons at the end of the courses) and the courses are more explanatory which I found helped me clarify what I was still unsure of after doing level 1 and 2
Big thank you to everyone who replied. Yes it makes it all much clearer. I have been referring to the newer challenges, although the older lessons are still very useful.
Thanks