An addendum to my post on learning pronunciation.

Break it down
A good tip for dealing with long, complicated words is to break them down into syllables, and to start at the end of the word rather than the beginning.

Let's say you're trying to learn how to say 'hunangyflogedig', which means 'self-employed' in Welsh. Don't start from the 'hun-', start from the '-dig' and build it up from there:

-dig
-gedig
-flogedig
-gyflogedig
-nangyflogedig
hunangyflogedig

You can also split it into pieces, particularly where those pieces have meanings. In 'hunangyflogedig', 'hunan-' means 'self', 'cyflog' means 'salary, pay' ('cyflogi' means 'to employ'), and the '-edig' end means that the word is an adjective. So you can use these building blocks to help pronunciation too: hunan cyflog edig - hunangyflogedig.

(Note: The C -> G change in Welsh is called mutation and is a grammatical feature of the language.)

You can also use words from the same root to build up fluency in pronunciation, and increase your vocabulary at the same time. For example, 'llyfr' means 'book' in Welsh, and there are several words that use 'llyfr' as a root:

llyfr - book
llyfryn - booklet
llyfrgell - library
llyfrgellydd - librarian

By learning the simple 'llyfr' and working your way up to 'llyfrgellydd', you give yourself plenty of practice with the same/similar sounds which will increase your confidence as well as improve your pronunciation.

Don't get stressed
Every word is made up of syllables, and these syllables can be stressed or not stressed when pronounced, e.g. the stressed syllable in 'pedestrian' is the second syllable: pedESTrian. Try saying PEDestrian, or pedestriAN and you'll see how awkward they sound.

When you are learning pronunciation, you also need to learn where the stresses are. Compare the English pronunciation of narrator and the French narrateur: In English, we stress the second syllable, narRATor, whereas in French it's on the last syllable, giving us narraTEUR.

In English, the stress moves about quite a bit. For example:

hoMOGenate
homoGENeous
homogeNETic
diSEMble
DISsonant

In French, the stress is always on the last syllable:

mousquetAIRE
incroyABLE
connaisSEUR
restauRANT
pampleMOUSSE

In Welsh, it's always the syllable from last:

PWYSig
pwySIGrwydd
llawYSgrif
llawysGRIFen
hunanymwyBODol

Learning to get the stresses right will help you sound much more like a native speaker and will help your pronunciation too. It may feel uncomfortable to start with, particularly if the stresses are different to those you are used to, but you will get used to it.