「あなたは言葉を選ぶのが下手ですね」= You are bad at picking words. / You are bad at choosing words.
「あなたは〜です」= You are...
「言葉」= word(s)
「選ぶ」= (to) pick; (to) choose
「下手」= bad (at); poor (at); not skilled (at)
になります。
ご参考までに。
You don't seem to think about your words much before you talk.
少し柔らかい、丁寧な言い方を2つ紹介します。
① You're not very good at choosing your words.
あなたは言葉を選ぶのがあんまり上手くないですね。
② You don't seem to think about your words much before you talk.
あなたは、話す前に自分の言葉をあんまり考えていないように見えます。
You're not very good at〜 あなたは〜があんまり上手くないです。
choosing your words （あなたの・自分の）言葉を選ぶこと
You don't seem to〜much あなたはあんまり〜するように見えないです。
think about your words （あなたの・自分の）言葉を考える
before you talk （あなたが）話す前に
① You are not very good at putting your ideas/thoughts into words.
② You are not very good at choosing the right words.
★ポイント：2パターン推測しました☺
なかなか思っていることを言葉にできないもどかしい感じの人に
① You are not very good at putting your ideas/thoughts into words.
「君、なんでここでそういう言葉選ぶかなー」っという感じの人に
② You are not very good at choosing the right words.
英語職人☺
You are not good at choosing/selecting the correct word?
You are not good at choosing/selecting the correct word?
select= to chose or pick something
choosing= when you have different options and pick one (you have chosen)
You are not good at choosing/selecting the correct word?
（あなたは的確な言葉を選ぶのが苦手ですね）
select= 選ぶ
choosing= いくつかの選択肢から選ぶこと
"You don't seem to think about your words much before you say them"
"You don't think before you speak"
If you believe that someone is irresponsible with the words that they choose to say, you can say something such as, "You're not very good at choosing words", "You don't seem to think about your words much before you say them" or "You don't think before you speak". All three of these sentences explain that you believe this person should pick their words better.
言葉に無責任だなと思う人がいるなら、次のように言えます。
"You're not very good at choosing words"（あなたは言葉を選ぶのが上手じゃない）
"You don't seem to think about your words much before you say them"（あなたは話す前にあまり考えていないように見える）
"You don't think before you speak"（あなたは話す前に考えない）
どの文も、言葉の選び方に注意した方がいいと伝えています。
Your choice of words leaves something to be desired
If a statement or action 'leaves something to be desired' it means that there is something missing or imperfect in such statement or action. In other words, it is not as good as it should be.
'John completed his task but the end result left something to be desired.'
［発言または行動 + leaves something to be desired］は「〔発言または行動は〕何かが欠けている［欠点がある］」という意味です。つまり、「イマイチ」ということです。
'John completed his task but the end result left something to be desired.'
（ジョンは仕事を完了させたが仕上がりはイマイチだった）
You have a problem when it comes to choosing words
"You are not good with words." is a brief and casual way of saying that someone has a weakness when it comes to picking up words.
"You seem to struggle with selecting words." is a more polite way of telling someone gently that they are not good at choosing the right words.
"You have a problem when it comes to choosing words" to 'have a problem with' can mean to have difficulties when it comes to doing something..
"You are not good with words."（あなたは言葉がうまくない）
これは、言葉を選ぶのがうまくないと伝える簡潔でカジュアルな言い方です。
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"You seem to struggle with selecting words."（あなたは言葉を選ぶのに苦労しているように見える）
これは言葉を選ぶのがうまくないと伝える丁寧な言い方です。
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"You have a problem when it comes to choosing words"（あなたは言葉を選ぶのに苦労している）
'have a problem with' には「（～するのに）苦労している」という意味があります。
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