▁On ▁the ▁other ▁hand , ▁s ynt actic ▁parsing ▁may ▁be ▁used ▁to ▁extract ▁multi - word ▁terms ▁or ▁phrase ology ▁from ▁a ▁source ▁text . ▁So ▁parsing ▁is ▁used ▁to ▁normal ise ▁word ▁order ▁variation ▁of ▁phrase ology , ▁this ▁is ▁which ▁words ▁can ▁form ▁a ▁phrase . ▁Seg ment ation ▁ ▁Its ▁purpose ▁is ▁to ▁choose ▁the ▁most ▁useful ▁translation ▁units . ▁Seg ment ation ▁is ▁like ▁a ▁type ▁of ▁parsing . ▁It ▁is ▁done ▁mon ol ing ually ▁using ▁super f icial ▁parsing ▁and ▁alignment ▁is ▁based ▁on ▁segment ation . ▁If ▁the ▁transl ators ▁correct ▁the ▁segment ations ▁manually , ▁later ▁versions ▁of ▁the ▁document ▁will ▁not ▁find ▁matches ▁against ▁the ▁T M ▁based ▁on ▁the ▁corrected ▁segment ation ▁because ▁the ▁program ▁will ▁repeat ▁its ▁own ▁errors . ▁Trans l ators ▁usually ▁proceed ▁sentence ▁by ▁sentence , ▁although ▁the ▁translation ▁of ▁one ▁sentence ▁may ▁depend ▁on ▁the ▁translation ▁of ▁the ▁surrounding ▁ones . ▁Al ignment ▁ ▁It ▁is ▁the ▁task ▁of ▁defining ▁translation ▁correspond ences ▁between ▁source ▁and ▁target ▁texts . ▁There ▁should ▁be ▁feedback ▁from ▁alignment ▁to ▁segment ation ▁and ▁a ▁good ▁alignment ▁algorithm ▁should ▁be ▁able ▁to ▁correct ▁initial ▁segment ation . ▁Term ▁extra ction ▁ ▁It ▁can ▁have ▁as ▁input ▁a ▁previous ▁dictionary . ▁Moreover , ▁when ▁extract ing ▁unknown ▁terms , ▁it ▁can ▁use ▁parsing ▁based ▁on ▁text ▁statistics . ▁These ▁are ▁used ▁to ▁estimate ▁the ▁amount ▁of ▁work ▁involved ▁in ▁a ▁translation ▁job . ▁This ▁is ▁very ▁useful ▁for ▁planning ▁and ▁sched uling ▁the