The /ɜː / sound is a long vowel sound. The tongue maintains a neutral position.

Single syllable words: 

fur, sir, her, bird, dirt, stir, birth, term, firm, learn, pearl, work, world, worth, burn, turn, hurt, curse, purse, nurse, verge, merge, earth, search, church, first, thirst, burst, worst, curse, burst, heard, word, serve, nerve, curb, spur, blur, slur, purr, skirt, third, squirm, twirl, swirl, whirl, hurl

Two syllable words: 

turtle, purple, circle, fertile, verbal, thermal, terminal, servant, earnest, current, certain, version, burden, perfect, mergeable, personal, pervade, verdict, converge, preserve, dessert, determine, rehearsal, convert, forward, reverse, conserve, observe, nervous, purpose, surface, surplus, worship, merchant, flourish, courage, encourage, discourage, nurture, furniture, burglary, courtesy, earnestly, purposely, certainly, verbally, perfectly, nervously

Sentences: 

The verdict of the jury was that the burglar had a surly disposition and deserved to be sentenced to a term in prison.

Her verbal assertion stirred fervour and earned her the eternal respect of the stern sergeant.

The entrepreneur's shrewd business acumen allowed her to merge with several other firms.