Scadinavian characters in regular expressions

Can someone please explain the following?
I am using a regular expression to find strings containing two words (begin
with one or more characters not being spaces followed by a space followed by
one or more characters not being spaces).
But when scandinavian characters are included it returns different results
depending on where the character is positioned.
The first two-word example returns TRUE as expected.
The second three-word example returns FALSE as expected.
But when I let an å (&#229 &aring a-ring) traverse through the string it
unexpectedly returns TRUE when the character is positioned as the
second-last or last character in the two first words.

SELECT 'one two' ~ '^[^ ]+[ ][^ ]+$'; returns TRUE
SELECT 'one two three' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE
SELECT 'åone two three' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE
SELECT 'oåne two three' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE
SELECT 'onåe two three' ~ '^[^ ]+[ ][^ ]+$'; returns TRUE
SELECT 'oneå two three' ~ '^[^ ]+[ ][^ ]+$'; returns TRUE
SELECT 'one åtwo three' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE
SELECT 'one tåwo three' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE
SELECT 'one twåo three' ~ '^[^ ]+[ ][^ ]+$'; returns TRUE
SELECT 'one twoå three' ~ '^[^ ]+[ ][^ ]+$'; returns TRUE
SELECT 'one two åthree' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE
SELECT 'one two tåhree' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE
SELECT 'one two thåree' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE
SELECT 'one two thråee' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE
SELECT 'one two threåe' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE
SELECT 'one two threeå' ~ '^[^ ]+[ ][^ ]+$'; returns FALSE

Thank you for any response.

Søren Vainio, Denmark