After the 1st Spouse visa you will need an extension. At the moment at that stage you would still need the same A1 level, so at the moment you wouldn’t need to worry about this rule at all. From May 2017, however, you need to demonstrate a higher A2 level when applying for extension. This new rule, having to prove A2 level, applies to those whose current Spouse / Partner visa expires from 1 May 2017 onwards – even if applying for extension before that! You can read more on this here in the earlier post: http://1st4immigration-visas.blogspot.co.uk/2017/02/new-a2-english-language-requirement.html
After that you could normally apply for a permanent visa. This is where an even higher B1 level would be needed.
We also have a recent post on how many levels there are: http://1st4immigration-visas.blogspot.co.uk/2016/12/english-language-for-uk-visa.html
If you are an Immigration Adviser or a Solicitor please visit our immigration Training and CPD website: www.1st4immigration.com/training We have a weekend OISC Level 1 course as well as a Points-Based System course and we also have online training courses, including Online OISC Level 1 course and courses focusing on Spouse/Partner visas. All our training courses are CPD-accredited with CPD credit accepted by OISC.