Step 1: Identify the regions that mean "exactly one language, and not French".
In the four-circle diagram, region a is the part of the Russian circle that does not touch English, French or Spanish, so a counts people who know only Russian. In the same way, region c is the part of the English circle lying outside all the other circles, the only-English group, and region e is the part of the Spanish circle lying outside all the other circles, the only-Spanish group. Region g is the only-French group.
Step 2: Work out the values.
We are told \(a = 40\). Using \(c = 2a\), \(c = 2 \times 40 = 80\). Using \(e = \frac{1}{2}a\), \(e = \frac{1}{2} \times 40 = 20\).
Step 3: Add the three "only" groups that are not French.
"Any one language except French" means a person knows exactly one of the four languages, and that language is not French. So we add the only-Russian, only-English and only-Spanish counts: \(a + c + e = 40 + 80 + 20 = 140\). Region g, the only-French group, is left out because the question excludes French.
Final Answer:
140 people can read and write any one language except French. \[ \boxed{140} \]