How are inline-tags extracted by search engines or screen readers?

Question

Let's take this as an example, where the heading is in normal font weight, but the two digits and the last part of the logo are written in bold:

<h1>20<span>14</span> Stack<span>overflow</span> takes over</h1>

How is this read by search engines and screenreaders? Does it result in:

2014 Stacokoverflow takes over

or:

20 14 Stack overflow takes over

Woud it be necessary to add the whole text in the title-attribute?

<h1 title="2014 Stacokoverflow takes over">[…]</h1>

Answer 1

Screen readers with default settings will read the full number 2014. However, a user may enable font changes announcement, and in this case he/she would hear "20 bold 14".
As for title, there's no great sense to do this since (again, by default) titles are ignored if there is some text between the opening and closing tags.