The grammar, although the world recognizes Indonesian has a relatively simple grammar, it won't be easy for people whose mother language isn't South East Asian.

Hello. I'm Taiwanese. I speak Chinese. I think pronunciation is very simple but the grammar compare to English that is difficult.
Although I can understand all the vocabulary meaning but all the vocabulary put it together I could't  understand what you are talking  about.

<pre class="tw-data-text tw-ta tw-text-small" data-placeholder="翻譯" id="tw-target-text" style="text-align: left; height: 120px;" data-fulltext="" dir="ltr">你好。我是台湾人。我说中文。我觉得语音很简单，但语法比较难以对英语。 虽然我能理解所有词汇的含义，但所有词汇都汇集在一起​​，我不明白你在说什么。</pre>

the language maybe easy to learn because we dont have so many rules/ grammars, the most difficult for foreigners to learn is when we are doing chat via texting or daily informal conversation, because we use alot of slangs and shortening a word , that usually confusing for non native , i can help if u wanna know something :) just let me know